IRLF 


HYSIOLOQY 
£T  HYGIENE 

FOR  CHILDREN 


PHYSIOLOGY  as 

FOR   CHILDREN 


BY 

EGBERT    EADIE 

Principal  of  School  72,  Borough  of  Queens, 
New  York  City, 

AND 

ANDREW   EADIE,   M.D. 

Professor  of  Physiology,  Ontario  Medical 
College  for  Women,  Toronto,  Canada. 


NEW   YORK 
CHARLES   SCRIBNER'S  SONS 

1909 


COPYRIGHT,  1904, 
Br  UNIVERSITY  PUBLISHING  CO. 


ENTEBED  AT  STATIONERS'  HALL, 
LONDON,  ENGLAND. 


COPYRIGHT,  1908, 
BY  CHARLES  SCRIBNER'S  SONS 

EDUCATION  DEPT. 


PREFACE 

IT  is  important  that  every  boy  and  girl  shall  become  familiar, 
while  at  school,  with  the  primary  laws  of  health.  A  knowledge 
of  the  structure  of  the  body,  its  parts,  and  their  uses,  is 
the  foundation  for  an  intelligent  understanding  of  these  laws. 
Anatomy  and  physiology  are,  therefore,  treated  here  chiefly  as 
an  aid  to  the  teaching  of  hygiene.  • 

In  order  that  children  may  readily  understand  the  story  of 
their  bodies,  it  is  told  in  clear,  simple  language,  and  with  a 
minimum  of  technical  terms. 

Great  care  has  been  taken  in  the  treatment  of  each  chapter 
and  topic  to  observe  the  relative  importance  of  the  various 
organs.  Those  which  have  more  important  functions  are  de- 
scribed in  greater  detail  than  those  whose  functions  are  less 
important.  The  interdependence  of  organs  has  also  been  kept 
prominently  in  view,  in  order  that  the  pupil  may  realize  that 
he  is  learning  about  an  active  living  body,  and  not  about 
isolated  parts. 

The  value  of  this  book  as  a  teaching  instrument  is  greatly 
enhanced  by  the  best  illustrations  that  could  be  obtained.  The 
authors  were  given  carte  blanche  by  the  publishers,  and  in- 
structed to  spare  no  expense  in  securing  pictures  that  would 
illustrate  the  text  in  the  best  possible  manner.  Color  has  been 
used  to  make  the  illustrations  more  attractive,  and  also  to  make 


4  PKEFACE 

it  easier  to  differentiate  parts,  but  there  has  been  no  uniform 
attempt  to  imitate  the  natural  color  of  the  parts. 

The  law  requiring  that  twenty-five  per  cent,  of  the  text  mat- 
ter shall  treat  of  "  the  nature  and  effects  of  alcoholic  drinks 
and  other  narcotics  "  has  been  complied  with.  The  injurious 
effect  of  alcohol  upon  different  organs  is  stated  plainly  and  con- 
cisely ;  and,  in  addition  to  that,  as  much  emphasis  as  possible 
has  been  placed  upon  the  positive  benefits  in  improved  health 
and  strength  which  arise  from  abstinence  from  the  use  of  alco- 
holic drinks  and  tobacco.  In  order  that  this  lesson  may  make 
a  deep  and  lasting  impression,  it  is  presented  in  the  concrete 
form  of  letters  written  by  men  whose  opinions  will  at  once  be 
accepted  as  worthy  of  confidence. 

The  authors  take  pleasure  in  acknowledging  their  obligations 
to  the  gentlemen  who  kindly  furnished  the  letters  contained 
herein,  and  also  to  Mr.  M.  Anagnos,  Director  of  The  Kinder- 
garten for  the  Blind,  in  Boston,  Mass.,  for  annual  reports  con- 
taining the  story  of  Thomas  Stringer. 


CONTENTS 


CHAPTER  PAGE 

I. — INTRODUCTION 7 

II.— BONES 17 

III. — MUSCLES 33 

IV. — THE  FOUR  KINDS  OF  FOOD 45 

V. — DIFFERENT  ARTICLES  OF  FOOD 52 

VI. — How  OUR  FOOD  is  CHANGED  INTO  BLOOD         .                 .  60 
VII. — How  THE  BLOOD  BUILDS  UP  THE  BODY    .         .        .         .78 

VIII.— DRINKS  WHICH  CONTAIN  ALCOHOL 94 

IX.— BREATHING  . 106 

X.— THE  SKIN 115 

XI.— THE  BRAIN,  SPINAL  CORD  AND  NERVES    .         .        .         .  130 

XII.— THE  FIVE  SPECIAL  SENSES 141 

APPENDIX 159 

KEYS 193 

GLOSSARY 197 

INDEX  .  201 


CHAPTER  I 


THE    BODY 

A  LITTLE  boy  whose  name  was  Charles  lived  in  a 
great  city.  In  the  hall  of  his  father's 
house  stood  a  tall  clock,  and  little 
Charles  used  to  stand  before  it  and 
watch  the  heavy  pendulum  swing  back 
and  forth,  and  listen  to  the  regular 
tick-tock,  tick-tock,  like  a  voice  speak- 
ing to  him.  At  times  he  would  hear  a 
sudden  click,  and  then  out  would  ring 
a  bell,  clear  and  sweet,  telling  that  an- 
other hour  had  passed. 

What  made  the  pendulum  swing? 
What  made  the  hands  go  round? 
What  made  the  bell  ring  at  exactly  the 
right  time  every  hour  ?  Little  Charles 
could  not  tell.  So  day  after  day  he 
would  stand  and  watch  the  old  clock 
and  wonder  about  it. 


THE    OLD    HALL 
CLOCK. 


8 


•PHTSfOLOGY   FOR   CHILDREN 


One  morning  when  he  came  down 
stairs  there  was  no  sound  in  the  hall. 
He  looked  up  at  the  clock  and  saw  that 
the  pendulum  was  still.  The  clock  had 
stopped.  Later  in  the  day  a  strange 
man  came  to  fix  it.  Charles  watched 
him  as  he  took  off  the  front.  Inside 
were  wheels  and  chains  and  weights. 
The  man  took  the  wheels  out  one  by 
one,  polished  them,  oiled  them,  and  put 
them  back,  fitting  each  part  nicely  to 
the  other.  Then  he  wound  up  the 
weights,  put  the  front  on  the  clock 
again,  started  the  pendulum  to  swing- 
ing, and  once  more  Charles  heard  the 
INSIDE  THE  CLOCK,  peasant  tick-tock,  tick-tock,  to  which  he 
loved  to  listen.  Now  he  knew  what  made  the  hands 
go  round,  the  pendulum  move,  and  the  bell  ring.  It 
was  the  wheels  and  the  chains  and  the  weights  inside. 
While  Charles  had  often  wondered  about  the  clock, 
he  had  never  thought  very  much  about  himself.  And 
yet  a  boy  is  much  more  wonderful  than  a  clock.  It 
can  move  its  hands  only  round  and  round ;  he  can 
move  his  hands  in  every  direction.  It  can  say  only 
tick-tock;  he  can  say  whatever  he  wishes.  It  can 


THE  BODY  9 

stand  only  where  it  is  placed;  he  can  run  and  jump 
and  play.  What  gives  a  boy  the  power  to  do  all 
these  things  ?  Would  you  like  to  know  ? 

The  body  of  a  boy,  like  the  body  of  a  clock,  has 
many  strange  things  inside — not  wheels,  chains  and 
weights,  but  other  things  which  are  just  as  strange, 
and  which  all  work  together.  The  picture  on  page  1 1 
shows  part  of  a  body  with  the  front  taken'  off.  Look 
at  it  and  you  will  see  some  of  these  things. 

From  this  little  book  you  can  learn  something  about 
your  body  and  the  things  inside  it.  Each  chapter 
tells  you  the  name  of  some  part  of  the  body,  how  it 
looks,  and  where  it  is ;  that  is  ANATOMY.  Next,  it  tells 
you  the  use  of  each  part ;  that  is  PHYSIOLOGY.  And 
then  it  tells  you  how  to  take  care  of  each  part;  that 
is  HYGIENE. 

The  body. — We  often  call  that  part  of  a  man  which 
you  see  in  the  picture  the  body,  but  its  real  name  is 
the  trunk.  The  upper  part  of  the  trunk  is  the  chest, 
the  lower  part  is  the  abdomen.  Joined  to  the  trunk 
are  the  head,  arms  and  legs.  All  these  together  make 
the  body. 

Organs. — The  works  of  a  clock  are  called  a  ma- 
chine. They  are  made  to  do  special  work,  and  are 
afterwards  put  into  the  body  of  the  clock.  The 


10  PHYSIOLOGY   FOB  CHILDREN 

strange  things  that  you  see  in  the  chest  and  abdomen 
also  do  special  work,,  but  they  are  called  organs. 
They  grow  in  the  body  from  the  first,  and  are  parts 
of  it.  Each  part  of  the  body  that  does  special  work 
is  called  an  organ.  The  eye  is  an  organ  of  sight.  The 
ear  is  an  organ  of  hearing.  The  hands  and  feet  also 
are  organs. 

Many  organs  are  very  delicate,  and  so  we  find  them 
placed  in  hollow  cases  of  bone,  called  cavities,  to  keep 
them  from  being  injured.  For  this  reason  the  brain, 
which  is  the  organ  of  the  mind,  is  shut  up  in  the 
skull,  and  many  important  organs  are  shut  up  in  the 
large  cavities  of  the  trunk. 

Look  at  the  picture  on  page  1 1  and  you  will  see  the 
ribs  and  the  breast  bone,  which  protect  the  cavities. 
Behind  the  ribs  are  organs  called  lungs.  In  the  centre 
of  the  neck  you  can  see  a  tube  called  the  windpipe, 
which  extends  upwards  from  the  lungs.  The  air 
which  you  breathe  passes  through  the  windpipe  into 
the  lungs.  Both  the  lungs  and  the  windpipe  have 
been  colored  purple  in  the  picture. 

Turn  to  the  picture  on  page  14.  The  ribs  have 
been  taken  off,  one  lung  has  been  taken  out,  and  the 
other  lung  has  been  drawn  back  so  that  you  can  see 
the  cavity  of  the  chest.  There  you  will  see  an  organ 


A    VIEW    OF   THE    INSIDE  OF    THE    TRUNK. 
(See  Appendix  for  Key.) 


12 


PHYSIOLOGY   FOE   CHILDREN 


called  the  heart,  colored  red.  Above  the  heart  are  red 
and  blue  tubes  which  go  from  it  to  other  parts  of  the 
body.  Just  under  the  heart  and  lungs  you  can  see 
the  partition  which  separates  the  chest  from  the  ab- 
domen. Below  this  partition  is  an  organ  called  the 
liver.  Below  the  liver  is  the  stomach.  In  the  picture 
the  liver  has  been  colored  brown,  and  the  stomach  yel- 
low, with  red  lines  over  it.  A  tube  goes  from  the 
mouth  down  to  the  stomach.  It  is  just  behind  the 
windpipe,  and  so  cannot  be  shown  in  the  picture.  It 
is  through  this  tube  that  food  passes  from  the  mouth 
to  the  stomach.  Below  the  stomach,  neatly  folded 

and    curled    up,  is   the 
intestine. 

Although  the  body 
has  many  organs,  all 
work  together  and  help 
one  another.  If  one 
organ  is  in  pain  and 
cannot  do  its  usual 
work,  other  organs  share 
the  injury  and  are  unable  to  do  their  work  well. 

Cells. — If  you  cut  open  a  ripe  orange  and  pick  it 
apart  carefully,  you  will  find  that  it  is  made  up  of  a 
great  number  of  little  sacs  which  are  full  of  juice. 


THE     CELLS     OF    AN     ORANGE  : 
SACS   FULL    OF  JUICE. 


LITTLE 


THE  BODY  13 

These  are  called  cells.  They  are  packed  closely  aiid 
are  held  together  by  small  threads,  or  fibres.  The 
fibres  in  the  orange  are  found  either  as  small  threads, 
or  woven  together  in  thin  sheets  like  tissue  paper. 

All  vegetables  and  animals  are  made  up  of  cells. 
Every  part  of  your  body,  every  organ  in  it,  all 
your  muscles  and  bones,  your  skin  and  hair  are  built 
up  of  cells.  Most  cells  are  so  small  that  you  cannot 
see  them  unless  they  are  made  to  look  much  larger 
than  they  really  are  by  the  use  of  a  microscope.  This 
is  true,  for  example,  of  the  cells  of  a  grain  of  wheat, 
a  potato  or  a  blade  of  grass.  It  is  also  true  of  the 
cells  of  muscle,  bone,  skin,  and  hair. 

Cells  are  held  together  by  little  fibres.  Many  of 
these  fibres  are  joined  together  into  sheets,  or  tissues. 
Because  these  tissues  connect  cells  and  hold  them 
together,  they  are  called  connective  tissue. 

Growth  and  health  of  the  body. — We  g;row 
rapidly  in  early  life.  As  the  years  pass  by  we  grow 
more  and  more  slowly,  but  continue  to  grow  until 
about  our  twenty-fifth  year.  Part  of  a  child's  food  is 
used  to  make  him  grow,  and  so  he  requires  more  to 
eat  in  proportion  to  his  size  than  a  grown  person  does. 

Exercise  and  work  that  is  not  too  hard  promote 
growth  and  health. 


ANOTHER   VIEW   OF   THE    INSIDE    OF   THE   TRUNK. 
(See  Appendix  for  Key.) 


THE    BODY  15 

Plain  wholesome  food  and  pure  drinking  water  are 
necessary  to  health. 

Pure  air  and  sunshine  are  also  necessary  for  health 
and  growth.  Notice  the  sickly  plants  that  are  kept 
too  long  in  a  north  window,  or  in  a  cellar,  where  the 
sun  cannot  shine  on  them.  Notice,  too,  how  pale  are 
the  unfortunate  children  who  are  crippled  and  unable 
to  run  about  outdoors.  Whatever  else  you  may  be 
afraid  of,  never  be  afraid  of  sunshine  and  fresh  air. 

The  continued  use  of  alcoholic  liquors  and  tobacco 
often  injures  the  body.  The  harm  that  they  do  to 
some  parts  of  the  body  may  be  serious  enough  to  re- 
quire the  aid  of  a  physician,  who  treats  such  injury 
with  as  much  care  as  if  it  were  due  to  accident  or 
contagion. 

Besides  the  physician,  the  employer  of  labor  knows 
that  alcoholic  liquor  and  tobacco  injure  the  body;  for 
he  finds  that  they  unfit  a  man  for  doing  his  best  work. 
In  fact;  many  people  refuse  to  employ  a  young  man 
who  uses  alcohol  or  cigarettes;  and  it  is  an  advantage 
to  a  young  man  in  any  calling  or  profession  if  it  is 
known  that  he  abstains  entirely  from  the  drinking  of 
alcoholic  liquor. 

The  following  letter  from  Mr.  John  Claflin,  President 
of  one  of  the  largest  dry  goods  companies  in  the  United 


16  PHYSIOLOGY  FOR   CHILDREN 

States,  illustrates  the  opinion  held  by  prominent  business 
men  in  regard  to  the  drinking  of  alcohol: 

THE  H.  B.  CLAFLIN  COMPANY, 

NEW  YORK,  April  26,  1907. 

My  Dear  Sir : — I  do  not  knowingly  employ  a  young  man  who 
uses  alcohol.  Its  use,  even  occasionally,  renders  him  unreliable 
and  impairs  his  ability  to  do  intelligent  and  constant  work.  In  the 
struggle  for  success  in  life,  the  total  abstainer  has  a  great  advan- 
tage over  the  moderate  drinker.  The  immoderate  drinker  is  out 
of  the  race. 

Very  truly  yours, 

(Signed)     JOHN  CLAFLIN, 

President. 

We  have  learned  that : 

1.  The  body  consists  of  distinct  parts. 

2.  Anatomy  tells  us  what  the  different  parts  of  the  body  are  like 

3.  Physiology  tells  us  the  uses  of  the  par.ts  of  the  body. 

4.  Hygiene  tells  us  how  to  take  care  of  the  body,  s 

5.  An  organ  is  any  part  of  the  body  that  has  a  special  work  to  do. 

6.  Some  of  the  most  important  organs,  such  as  the  brain  and  heart,  are 
contained  in  cavities  in  the  body. 

7.  The  body  is  made  up  of  cells  held  together  by  connective  tissue. 

8.  The  use  of  alcoholic  liquors  and  tobacco  often  injures  health. 


CHAPTER  II 


THE  FRAMEWORK    OF    A    COTTAGE. 


BONES 

The  framework  of  the  body. — In   this   picture 
you  can  see  a  cottage  which  carpenters  are  building. 

They  have  fastened  to- 
gether strong  pieces 
of  timber,  to  make 
the  framework.  This 
framework  will  give 
shape  to  the  cottage, 
and  support  its  parts. 
The  carpenters  will 
nail  boards  and  shingles  upon  the  outside,  and  will 
lay  floors  and  put  in  doors  and  windows.  The  frame- 
work will  support  all 
of  these,  and  the  fin- 
ished cottage  will 
look  like  the  one  in 
the  second  picture. 

The  human  body 
has  a  framework  of 
bones  which  gives  to 
the  body  its  general 


THE   FINISHED    COTTAGE. 


18 


PHYSIOLOGY  FOR  CHILDREN 


THE  FRAMEWORK,  OR  SKELETON,  OF  THE  BODY. 


BONES 


19 


shape.  It  supports  the  flesh  which  is  laid  over  it,  and 
also  protects  the  tender  parts  of  the  body  which  are 
placed  within  it.  If  the  skin  and  flesh  were  removed 
from  a  body,  so  that  you  could  see  this  framework, 
which  we  call  the  skeleton,  it  would  look  like  the 
picture  on  page  18. 

What  bones  are  made  of. — Bone  is  a  hard 
substance.  You  can  find  out  by  two  little  experiments 
something  about  the  materials  of 
which  bone  is  made. 

Place  a  bone  in  a  hot  fire  for 
three  or  four  hours.  It  will  keep  its 
shape,  no  matter  how  long  you  burn 
it;  but  if  you  try  to  handle  it  after 
it  is  burned,  it  will  crumble  to  pieces. 
The  part  of  a  bone  that  remains  af- 
ter it  has  been  burned  is  called  min- 
eral matter. 

Get  two  ounces  of  muriatic  acid 
at  a  drug  store,  and  put  the  acid 
and  a  pint  of  water  into  a  bottle. 
Then  put  the  leg-bone  of  a  chicken 
into  the  bottle,  and  leave  it  there 
four  days.  When  you  take  the  bone  out,  you  will 
find  it  so  soft  that  it  can  be  tied  into  a  knot.  The 


A  CHICKEN'S 
LEG-BONE  TIED 
INTO  A  KNOT. 


20  PHYSIOLOGY   FOE   CHILDREN 

part  of  a  bone  that  remains  after  it  has  been  in  acid 
is  called  animal  matter. 

The  fire  burned  away  the  animal  matter  of  one 
bone,  and  the  acid  dissolved  out  the  mineral  matter  of 
the  other  bone. 

The  animal  matter  in  bone  resembles  gristle.  It 
makes  the  bones  tough. 

The  mineral  matter  consists  largely  of  lime.  It 
makes  the  bones  hard  and  strong. 

In  early  life  the  bones  are  elastic  and  will  bend 
before  they  break.  As  people  grow  old  their  bones 
become  less  elastic  and  more  brittle.  It  was  long 
taught  that  this  brittleness  was  caused  by  a  loss  of 
animal  matter  and  an  increase  of  mineral  matter. 
Now,  however,  it  is  taught  that  bones  become  brittle 
with  age  because  they  lose  both  animal  and  mineral 
matter.  On  account  of  this  loss  the  bones  of  old 
people  are  not  strong  and  break  easily. 

How  bones  look. — If  you  examine  a  short  or  a 
flat  bone  which  has  been  well  dried,  you  will  find 
that  the  outer  part  is  hard  and  firm.  When  the 
bone  is  broken,  the  inner  part  is  seen  to  be  like  a 
sponge,  full  of  small  holes.  The  holes  in  the  spongy 
part  are  connected  with  one  another,  so  as  to  form 
little  canals. 


BONES  21 

A  long  bone  consists  of  a  round  shaft,  with  enlarged 
ends.  The  material  of  the  ends  is  like  that  of  a  short 
bone.  If  you  saw  the  shaft  across,  you  will  see  a  ring 
of  hard  bone  with  a  hollow  space 
running  through  it  from  end  to 
end.  This  hollow  space,  when  the 
bone  is  fresh,  contains  a  yellow 
substance  called  marrow,  which 
consists  largely  of  fat  and  small 
blood  tubes. 

A  fresh  bone  is  pinkish  white, 
because  it  contains  blood. 

An  old  dried  bone  is  white,  be- 
cause it  has  lost  the  blood  that 
was  in  it. 

Joints. — In  order  that  the  bones 
of  the   body   may    make  a   frame- 
work^ they   must   be   fastened    to- 
gether, just  as  pieces  of  timber  must 
be  fastened   together  to  make  the 
framework  of  a  cottage.     A  place         A  LONG  BONE- 
in  the  skeleton  where  bones  are  fastened  together  is 
called   a  joint.    Every  one  has  seen  the  hinges  on  a 
door.      They  are  simply  joints  of  metal,  which  allow 
the  door  to  open  and  close.     Many  of  our  joints  are 


PHYSIOLOGY   FOR   CHILDREN 


like  hinges ;  they  allow  bones  to  move  upon  one  an- 
other easily. 

To  understand  the  value  of  such  joints  you  have 
only  to  try  to  play  ball  without  bending  your  arms  at 
the  elbow,  or  to  write  without  bending  your  fingers  at 
the  knuckles,  or  to  walk  without  bending  your  knees. 

Some  joints,  like  those  of  the 
elbow  and  shoulder,  allow  the 
bones  to  move  freely.  Others, 
like  those  of  the  spine,  allow  the 
bones  to  move  only  slightly; 
while  the  joints  of  the  skull  are 
fixed — they  do  not  allow  the 
bones  to  move  at  all. 

The    ends    of    the   bones    at 
joints   which    allow    movement 
are     covered     with     a    tough, 
smooth    substance     called    car- 
tilage, which  is  elastic  like  rubber. 

The  bones  are  held  together  at  the  joints  by  short, 
tough,  white,  glistening  bands  of  connective  tissue, 
called  ligaments.  You  can  see  the  ligaments  of  the 
wrist  and  the  hand  in  this  picture. 

Ligaments  are  soft  and  bend  easily,  so  as  to  allow 
great  freedom  of  movement ;  yet  they  are  strong,  and 


LIGAMENTS  OF   WRIST 
AND   HAND. 


BONES 


23 


BONES  OF  THE  WRIST  AND  HAND. 

which  enough  of  this 
fluid  is  made  to  keep 
the  ends  of  the  bones 
slippery,  so  that  they 
move  smoothly  upon 
one  another. 

Chief  bones  of  the 
body. — It  takes  a  great 
many  bones  to  make 
the  skeleton.  There  are 
about  two  hundred. 
This  seems  a  large  nuni- 


tough,  and  hold  the  bones 
securely  in  their  right  places. 
The  hinges  of  a  door  some- 
times work  with  difficulty. 
A  drop  or  two  of  oil  will 
cause  them  to  move  freely. 
Many  of  our  joints  are  sup- 
plied with  a  fluid  which  helps 
them  to  move  easily,  as  oil 
helps  the  hinges.  The  inner 
surfaces  of  the  ligaments 
have  a  smooth  lining,  in 


BONES   OF   ANKLE   AND   FOOT. 


24  PHYSIOLOGY   FOR   CHILDREN 

ber,  but  all  are  needed.  Each  has  its  own  place  and 
its  own  use. 

Look  at  the  pictures  on  page  23  and  compare  the 
bones  of  the  wrist  and  hand  with  those  of  the  ankle  and 
foot.  The  wrist  and  hand  contain  twenty-seven  bones. 
Can  you  find  them  all  in  the  picture  ?  The  ankle 
and  foot  contain  twenty-six  bones.  Count  them  in  the 
picture.  There  are  eight  small  bones  in  the  wrist  and 
seven  in  the  ankle  and  instep.  How  many  do  you  see 
in  the  palm  of  the  hand  ?  How  many  in  the  foot  be- 
tween the  instep  and  the  toes?  How  many  in  the 
thumb  ?  in  the  great  toe  ?  How  many  are  there  in 
each  of  the  other  toes  ?  How  many  in  each  of  the 
fingers  ?  The  bones  of  the  wrist,  hand,  and  fingers  are 
arranged  in  rows,  and  held  in  place  by  strong  liga- 
ments. These  ligaments  are  so  elastic  that  the  hand 
and  fingers  can  move  rapidly  and  easily  in  different 
kinds  of  work  and  play.  The  bones  of  the  foot, 
ankle,  and  instep  also  are  held  together  by  strong  and 
elastic  ligaments. 

You  see  that  the  hands  and  feet  are  made  on  much 
the  same  plan,  yet  they  serve  very  different  purposes. 
It  is  not  easy  to  use  the  feet  as  we  use  the  hands,  to 
hold  and  handle  things,  because  the  toes  are  short,  and 
the  bones  of  the  great  toe  lie  side  by  side,  or  parallel 


BONES  25 

with  the  bones  of  the  other  toes.  The  bones  of  the 
thumb  are  not  parallel  with  those  of  the  fingers,  but 
are  so  arranged  that  the  tip  of  the  thumb  can  be 
made  to  touch  the  tips  of  the  fingers.  This  is  im- 
portant, for  it  gives  us  power  to  grasp  and  hold 
with  the  hands. 

Now  turn  back  to  the  picture  of  the  skeleton  on 
page  1 8  and  compare  the  bones  of  the  arm  with  those 
of  the  leg.  How  many  bones  do  you  find  from  the 
shoulder  to  the  elbow  ?  From  the  hip  to  the  knee  ? 

There  is  one  small  bone  which  forms  the  front  of 
the  knee  and  protects  it.  It  is  called  the  knee-cap. 
The  elbow  has  no  such  bone.  How  many  bones 
extend  from  the  elbow  to  the  wrist  ?  How  many 
extend  from  the  knee  to  the  ankle  ?  Which  is  the 
largest  bone  in  the  skeleton  ? 

The  backbone,  or  spine,  is  made  up  of  thirty- three 
bones,  which  are  placed  one  upon  another  like  spools 
on  a  string.  In  children  each  bone  is  separated  from 
the  one  above  it  and  from  the  one  below  it  by  a  thin 
layer  of  cartilage.  This  cartilage  allows  the  bones  to 
move,  so  that  the  spine  may  bend  and  turn  easily.  The 
cartilage  acts  also  as  a  cushion  to  prevent  injury  from 
a  sudden  jar.  In  grown  people  the  nine  lower  bones 
of  the  spine  are  united  so  as  to  form  only  two  bones. 


PHYSIOLOGY   FOK   CHILDREN 

Notice  this  picture  of  one  of  the  bones 
of  the  spine.  The  small  holes  on  either 
side  are  for  blood  tubes,  while  the  large 
hole  in  the  centre  is  for  a  delicate 
cord  which 
passes  down 
from  the  brain, 
and  is  called  the 
spinal  cord. 

The  spine  is 
sometimes  called 
the  spinal  col- 
umn, because  it  ONE  OF  THE  BONES  OF  THE 

SPINE. 

forms   a   strong 

column,  or  pillar,  to  support  the  upper 

part  of  the  body. 

The  skull  is  made  up  of  a  number 
of  bones  which  are  joined  at  their 
edges.  The  picture  on  page  27  shows 
where  some  of  the  bones  are  joined. 

The  skull  forms  a  box  that  holds  the 
brain.    In  the  front  part  of  it  are  two 
THE  SPINAL       hollows,  called  sockets,  for  the  eyes. 

COLUMN.  ~     ,  ,  „       , 

Only  the  upper  part   01  the  nose  is 
made  of  bone.    The  lower  part  is  composed  of  cartilage. 


BONES 


27 


A    VIEW    OF   THE   SIDE   OP   THE 
SKULL. 

the  spinal  cord  extends  from 
the  brain  downwards  into 
the  spine. 

The  ribs  form  a  bony 
cage  which  protects  the 
heart  and  lungs.  All  the 
ribs  are  fastened  to  the 
spine,  and  most  of  them  to 
the  breast-bone.  They  are 
moved  gently  upwards  and 
downwards  as  we  breathe. 

Look  at  the  picture  on 
the  next  page  and  tell  how 


The  lower  jaw  is 
fastened  to  the  skul] 
by  two  joints,  one  on 
each  side  of  the  face. 
The  jaw  can  move  up 
and  down,  and  also 
from  side  to  side. 

The  picture  below 
gives  a  view  of  the  base 
of  the  skull.  It  shows 
the  hole  through  which 


A   VIEW   OF  THE  BASE   OF  THE 
SKULL. 


28 


PHYSIOLOGY   FOE   CHILDREN 


many  ribs  you  see  on  each  side.  How  many  on  each 
side  are  fastened  directly  to  the  breast-bone  ?  How 
many  are  not  fastened  to  anything  in  front?  How 
many  are  fastened  in  front  to  ribs  above  them  ? 

The  collar-bone  can  easily  be  felt  at  the  upper  part  of 

your  chest  in  front.  It 
extends  from  the  shoul- 
der to  the  breast-bone, 
and  serves  as  a  prop  to 
the  shoulder. 

The  shoulder-blade,  as 
you  will  see  from  the' 
picture  of  the  skeleton, 
is  a  strong  bone  which 
is  spread  out  like  a 
fan  over  the  upper  ribs 
at  the  back.  At  the 
centre,  from  which  the 
fan  spreads,  is  a  shallow 
cup-like  cavity  into  which  the  upper  end  of  the  arm- 
bone  fits,  and  makes  the  shoulder-joint.  The  shoulder- 
blade  is  connected  with  the  collar-bone  also. 

Hygiene. — We  often  hear  that  "as  the  twig  is 
bent  the  tree  is  inclined."  This  is  certainly  true  of 
the  bones.  The  soft  bones  of  children  may  be  bent 


THE    RIBS    AND    BREAST-BONE. 


BONES 


into  awkward  shapes  by  wrong  positions  and  unsuit- 
able clothing.  If  the  bending  continues,  the  bones  will 
harden  into  these  shapes  and  the  body  will  be  de- 
formed. 


ill 


X-RAY  PHOTOGRAPH  OF  BONES  OF 
FOOT  WITHOUT  SHOE. 


X-RAY  PHOTOGRAPH  OF  BONES  OF 
FOOT  IN  SHOE. 


The  foot  may  be  forced  out  of  shape  by  tight,  or 
badly  fitting  shoes.  The  picture  on  the  left  was  taken 
without  the  shoe,  and  you  see  the  natural  shape  of  the 
foot.  The  picture  on  the  right  shows  how  the  bones  of 
the  foot  may  be  pressed  out  of  shape  by  a  tight  shoe. 


30 


PHYSIOLOGY   FOR   CHILDREN 


The  ribs  may  be  pressed  inward  by  tight  clothing 
about  the  waist.  In  this  way  internal  organs  are 
sometimes  pushed  out  of  place,  so  that  they  cannot 
do  their  work  as  they  should. 


FROM  AN   X-RAY   PHOTOGRAPH    OF   A  STRAIGHT   SPINE. 

Every  one  should  form  the  habit  of  sitting  and 
standing  upright.  By  constant  stooping  you  may 
become  round-shouldered.  If  you  form  the  habit  of 
holding  your  body  in  a  one-sided  or  stooping  posi- 
tion you  may  gradually  grow  out  of  shape,  and  you 


BONES 


31 


will    find    it   very   difficult,    or   even   impossible,    to 
straighten  up  again. 

For  this  reason  desks  in  a  school-room  should  al- 
ways be  suited  to  the  height  of  pupils.     If  the  desk 


FROM    AN   X-RAY    PHOTOGRAPH    OF    A    CURVED    SPINE. 

is  too  high,  the  right  shoulder  is  raised  above  the  left, 
and  the  body  will  be  bent  to  one  side.  If  the  desk 
is  too  low,  the  habit  of  stooping  will  be  formed,  and 
the  pupil  will  become  round-shouldered.  Here  we  have 
the  picture  of  the  spine  of  a  girl  when  she  was  seven- 


32  PHYSIOLOGY   FOB   CHILDREN 

teen  years  of  age.  Her  spine  became  curved  while 
she  was  attending  school. 

The  seat  should  be  so  arranged  as  to  allow  the 
feet  to  rest  comfortably.  If  the  feet  have  no  sup- 
port their  weight  may  cause  the  thigh  bones  to  be 
bent  out  of  shape. 

A  sudden  twist  or  wrench  of  a  joint  may  over- 
stretch or  tear  the  ligaments  and  produce  an  injury 
which  is  called  a  sprain.  A  sprained  joint  should 
always  have  rest. 

We  have  learned  that : 

1.  A  framework  of  bones  gives  shape  to  the  body,  and  supports  and  pro- 
tects other  parts  of  it. 

2.  Bone  is  a  hard  substance  composed  of  animal   matter  and   mineral 
matter. 

3.  The  outer  part  of  all  bones  is  hard  and  firm,  the  inner  part  is  either 
spongy  or  hollow. 

4.  A  joint  of  the  body  is  a  place  where  two  bones  are  fastened  together. 

5.  The  ends  of  the  bones  of  a  movable  joint  are  covered  with  cartilage, 
and  are  held  together  by  ligaments. 

6.  Movable  joints  are  furnished  with  oil. 

7.  Bones  may  be  forced  out  of  shape  and  may  remain  so. 


CHAPTER  III 

MUSCLES 

What  muscles  do  for  us. — A  bit  of  stone  from 
the  mountain  side  may  travel  down  to  the  seashore 
and  become  one  of  the  pebbles  at  the  water's  edge, 
but  in  its  long  journey  it  never  moves  itself.  The 
rain  washes  it  down  into  a  stream,  and  the  stream 
carries  it  to  the  shore. 

A  seed  that  falls  to  the  ground  wrould  perhaps 
grow  better  in  the  soil  of  a  neighboring  field,  but  it 
cannot  get  there  unless  the  wind  carries  it.  It  has  life, 
but  it  has  no  power  to  move. 

Watch,  however,  the  graceful  movements  of  a  bird  as 
it  flies  from  tree  to  tree.  It  can  make  these  move- 
ments because  it  has  muscles.  The  movements  of  all 
animals,  from  the  tiny  insect  to  the  great  elephant,  are 
due  to  muscles.  Even  the  slightest  motion  of  the 
body,  such  as  the  winking  of  an  eyelid,  is  produced  by 
muscles. 

When  a  ball  is  lying  on  the  floor  it  has  no  power  to 
move  itself,  and  when  rolling  it  has  no  power  to  stop 
itself.  But  if  a  boy  is  running  he  can  stop  when  he 
chooses,  because  he  has  muscles.  Our  muscles  not 


34  PHYSIOLOGY   FOE  CHILDREN 


THE  MUSCLES  OF  THE  SURFACE  OF  THE  BODY. 


MUSCLES  35 

only  enable  us  to  move ;  they  also  enable  us  to  keep 
from  moving.  It  is  by  means  of  our  muscles  that  we 
can  hold  an  arm  out  straight  from  the  shoulder,  and 
sit  or  stand  upright.  When  we  become  weak  from  ill- 
ness, we  have  to  lie  in  bed  because  our  muscles  can- 
not hold  us  up. 

The  muscles  serve  still  another  purpose.  They 
cover  the  skeleton  and  give  to  the  body  its  graceful 
curves  and  beautiful  outline. 

Very  few  boys  and  girls  have  ever  seen  a  whole 
muscle,  but  every  one  has  seen  a  beefsteak,  and  that  is 
a  slice  of  muscle.  We  are  eating  muscle  whenever  we 
eat  the  lean  flesh  of  a  chicken,  lamb,  or  other  animal. 

How  muscles  act. — On  the  left  we  have  a  picture 
of  a  muscle  taken  from  the  leg  of  a  frog.  If  this 
were  a  real  muscle  instead  of  a  picture, 
and  we  were  to  prick  it  with  a  pin,  it 
would  at  once  become  shorter ;  that  is, 
it  would  contract.  It  would  then  look 
like  the  picture  on  the  right.  After  con- 
tracting, a  muscle  will  return  to  the 
shape  that  it  had  before  ;  that  is,  it  will 
relax.  It  is  by  means  of  their  power 
to  contract  and  relax  that  the  muscles 
are  able  to  move  the  body.  A  FROG. 


LEG   MUSCLE    OP 


3(5 


PHYSIOLOGY   FOE   CHILDREN 


Bare  your  right  arm,  and  hold  it  up 
before  you,  with  the  palm  of  the  hand 
toward  you.  Close  your  hand  and  then 
open  it  again.  Watch  the  arm  while 
you  do  this,  and  you  will  see  muscles 
lying  along  the  front  of  it  contract  and 
pull  your  fingers  down.  Then  muscles 
lying  along  the  back  of  it  contract  and 
pull  the  fingers  up  again. 

Here  are  pictures  of  the  bones  of  the 
arm,  with  one  muscle  in  its  natural  posi- 
tion. The  other  muscles  of  the  arm  are 
not  shown. 
The  upper 
end  of  this 
muscle  is 
fastened  to 
a  bone  at 
the  shoul- 
der, and  the 

lower  end   is    fastened  to 
another  bone  below  the  el- 
bow.     When  this  muscle 
contracts,  it  pulls  on  the  bone  to  which  its  lower  end  is 
fastened,  and  the  forearm  and  hand  are  moved  upward. 


UNCONTR ACTED 
MUSCLE  OF 
UPPER  ARM. 


CONTRACTED    MUSCLE    OF    UPPF.R 
ARM. 


MUSCLES  37 

Why  muscles  contract. — In  our  bodies  there  are 
many  silvery  threads,  called  nerves,  which,  like  tele- 
graph wires,  carry  messages.  Whenever  you  decide 
to  move  your  arm,  your  hand,  or  any  part  of  your 
body,  a  message  is  sent  out  by  your  brain.  This  mes- 
sage travels  quickly  along  a  nerve  to  the  proper  mus- 
cles, and  on  its  arrival  a  contraction  of  those  muscles 
takes  place.  Like  faithful  servants  they  obey  your 
slightest  command. 

Kinds  of  muscles. — Some  muscles,  such  as  those  of 
the  arms  and  legs,  contract  only  when  we  order  them 
to  do  so.  They  are  under  the  control  of  our  will  and 
for  this  reason  they  are  called  voluntary  muscles. 

There  are  many  other  muscles  which  are  not  under 
the  control  of  the  will.  We  can  neither  make  them 
contract  nor  prevent  them  from  contracting,  so  they 
are  called  involuntary  muscles.  Your  heart  is  made 
up  of  involuntary  muscles.  You  have  no  control 
over  its  action ;  it  keeps  on  beating  whether  you  are 
awake  or  asleep. 

Shapes  of  muscles. — Muscles  are  of  many  differ- 
ent shapes  and  sizes.  Some  are  thin,  round  and  long; 
some  are  short  and  broad  ;  while  others  are  spread  out 
like  a  fan.  The  shape  and  size  of  each  are  suited  to 
the  work  it  has  to  do. 


38 


PHYSIOLOGY   FOE  CHILDREN 


THREE  FIBRES   OP  VOLUNTARY 
MUSCLE.      (Magnified.) 


What  muscles  are  made  of.— Muscles  are  made 
of  very  fine  threads,  or  fibres.  Here  is  a  picture  of 
three  fibres  of  voluntary  muscle,  very  much  magnified, 
and  also  a  picture  of  a  bundle  of  fibres.  Each  volun- 
tary muscle  consists  of  bundles  of  these  fibres.  The 

bundles  and  fibres  are 
held  together  by  con- 
nective tissue.  When 
lean  meat  is  boiled  the 
connective  tissue  is  soft- 
ened and  the  muscle 
can  be  easily  separated 

into   fine  threads,  and   yet   the  smallest  thread  con- 
sists of  many  fibres. 

The  tendons. — Some 
muscles  are  attached  at 
both  ends  directly  to 
bone.  Other  muscles 
end  in  white  glistening 
cords  which  are  fast- 
ened to  bone.  These 
cords  are  called  tendons.  The  tendons  are  composed 
of  hard  connective  tissue,  which  is  tough  and  strong 
and  will  not  stretch. 

If  you  look  at  the  back  of  your  hand  while  your 


A  BUNDLE    OF    MUSCLE    FIBRES. 
(Magnified.) 


MUSCLES  39 

fingers  are  working  rapidly,  you  will  see,  moving  under 
the  skin,  the  tendons  which  belong  to  the  muscles  on 
the  back  of  the  arm. 

Exercise. — Our  muscles  require  food.  They  get 
it  from  the  blood,  through  little  tubes.  Each  time  a 
muscle  contracts  these  little  tubes  become  larger,  and 
the  muscle  receives  an  increased  amount  of  food. 

Exercise  causes  the  muscles  to  contract  again  and 
again.  While  they  are  contracting  they  get  more  food 
from  the  blood,  and  therefore  increase  in  size  and 
strength.  It  is  because  of  more  exercise  that  the 
farmer's  boy  who  works  in  the  fields  is  generally 
stronger  than  the  boy  who  lives  in  the  city.  The 
blacksmith  can  pound  the  red  hot  iron  with  great 
force  because  his  muscles  are  large  and  strong,  but 
his  muscles  have  become  large  and  strong  because  for 
years  he  has  been  pounding  the  iron. 

Muscles  that  are  not  used  soon  become  small  and 
weak,  for  they  do  not  receive  proper  supplies  of  blood, 
and  so  are  not  well  fed.  This  is  shown  in  the  case 
of  a  broken  arm.  After  an  arm  has  been  in  a  sling 
for  a  few  weeks  its  muscles  become  so  weak,  from  lack 
of  exercise,  that  it  is  hard  for  them  to  make  even  ordi- 
nary movements. 

All  parts  of  the  body  should  be  exercised,  so  that 


40 


PHYSIOLOGY   FOB   CHILDREN 


one  part  may  not  remain  weak  while  other  parts  be- 
come strong.  Not  all  people  are  benefited  by  the  same 
kind  of  exercise.  Some  tire  sooner  than  others.  Some 
need  harder  work  than  others.  Therefore  it  is  foolish 
to  insist  on  taking  any  particular  exercise  merely 
because  some  one  else  finds  it  useful.  Such  exercises 
as  those  with  light  weights,  which  can  be  done  easily 


EXPERIMENT  TO  SHOW  EFFECT  OF  ALCOHOL 
ON  THE  MUSCLES. 


and  quickly,  will  benefit  a  person  more  than  exercises 
which  require  all  his  strength. 

Effect  of  alcohol  on  the  muscles. — Alcohol 
weakens  the  muscles.  Careful  experiments  to  show 
that  muscles  are  affected  by  small  quantities  of  alcohol 
were  recently  made  both  in  Switzerland  and  Belgium. 

This  picture  shows  how  these  experiments  were 
made.  The  arm  was  fixed  on  a  board  by  means  of 


MUSCLES  41 

two  clamps,  so  as  to  keep  it  still.  The  first  and  third 
fingers  were  placed  in  tubes,  which  kept  them  from 
interfering  with  the  second  finger.  A  string,  fastened 
to  the  second  finger,  was  passed  over  a  pulley  and 
attached  to  a  weight. 

o 

Every  time  the  second  finger  was  bent  upwards  the 
weight  was  lifted.  The  experiments  consisted  in  bend- 
ing and  straightening  out  the  finger  until  its  muscles 
became  so  tired  that  they  could  not  lift  the  weight 
again. 

It  was  found  that  the  muscles  of  the  finger  could  do 
more  work  when  no  alcohol  was  taken  than  they  could 
when  even  a  small  amount  was  taken. 

A  man  who  develops  his  muscles  by  exercise  until 
they  become  large  and  strong  is  called  an  athlete. 
The  following  letters  show  that  when  athletes  are  try- 
ing to  become  as  strong  as  possible  it  is;  usual  for  them 
to  do  without  alcohol  and  tobacco.  This  proves  that 
the  use  of  either  alcohol  or  tobacco  is  considered 
injurious  to  the  muscles. 

THE  CORNELL  NAVY. 
ITHACA,  K  Y.,  November  7,  1899. 

Gentlemen : — Answering  your  favor  asking  my  opinion  as  to 
the  use  of  alcoholic  liquors  and  tobacco  by  men  who  are  train- 
ing for  rowing  contests,  I  would  say  : 


PHYSIOLOGY    FOR   CHILDREN 


A    CREW    OF   ATHLETES. 

First :  As  to  alcoholic  liquors,  I  do  not  believe  in  the  use  of 
any  form  of  alcoholic  liquor  for  men  in  training.  I  know  that 
in  England,  and  sometimes  in  this  country,  it  is  used  by  other 
trainers,  but  I  have  found,  in  my  experience,  that  young  men 
are  much  better  off,  and  do  better  work  without  alcoholic  stim- 
ulants than  with  them,  and  they  are,  therefore,  absolutely 
prohibited  in  our  training.  The  use  of  alcohol  in  any  shape  I 
think  wholly  unnecessary  for  any  young  man  who  has  sufficient 
bodily  health  to  be  athletic,  and  in  many  cases,  as  I  know,  it  is 
positively  injurious  if  used. 

Second  :  As  to  tobacco,  I  believe  young  men  do  better  work 
when  not  using  tobacco  than  when  using  it,  and  it  is  prohibited 
in  our  training  here  at  Cornell  University. 
Respectfully  yours, 

CHAS.  E.  COURTNEY. 


MUSCLES  43 

NEW  YORK,  March,  12,  1900. 

Dear  Sir: — Eeplying  to  your  favor  of  the  10th  inst.,  I  will 
say  that  I  do  not  use  alcoholic  liquors  in  any  form,  neither 
do  I  use  tobacco.  I  have  never  used  them.  I  do  not  believe 
any  athlete  can  meet  with  success  who  does  use  either  alcohol 
or  tobacco. 

Respectfully  yours, 

FRANK  L.  KRAMER. 
(National  amateur  cycling  champion  of  America,  1898,  1899.) 

NEW  HAVEN,  CONN.,  Jan.  11,  1900. 

Dear  Sir: — Yours  of  the  10th  inst.  at  hand.  It  is  abso- 
lutely necessary  for  a  college  or  school  athlete  who  is  striving 
to  win  a  place  on  any  team  to  have  endurance;  especially  is  this 
true  in  rowing  and  football.  This  can  be  accomplished  to  the 
greatest  degree  only  by  abstaining  from  the  use  of  tobacco  and 
alcoholic  drinks  while  in  training  for  said  team. 
Very  truly  yours, 

M.  F.  MCBRIDE, 
Capt.  Yale  Football  Team  of  '99. 

173  BROADWAY,  NEW  YORK,  April  4,  1901. 

Dear  Sir: — There  is  nothing  which  goes  to  make  a  better 
athlete,  nothing  which  gives  a  man  greater  power  of  endurance 
than  total  abstinence  from  the  use  of  alcoholic  drinks  and 
tobacco. 

At  the  opening  of  college,  all  the  candidates  for  the  football 
team  are  called  together  and  informed  of  the  plans  for  the 
year.  They  are  also  told  at  what  date  rigid  training  will  begin. 
Those  men  who  are  using  liquor  and  tobacco  have  now  a  chance 


44  PHYSIOLOGY   FOR  CHILDREN 

gradually  to  leave  them  off  altogether,  so  that  at  the  set  date 
every  one  starts  in  on  good,  hard,  conscientious  work. 

At  Princeton,  there  have  been  several  opinions  given  in  re- 
gard to  the  use  of  ale  at  the  training  table.  In  some  years  the 
men  who  wished  to  have  it  have  been  given  one  glass  of  ale 
with  their  dinner,  and  many  believe  in  its  use.  Beer  and  other 
alcoholic  liquors  are  never  used.  I  think  a  team  is  better  off 
without  any  of  them. 

No   one  is  expected  to  use  tobacco.      A  man  who  is  using 
tobacco  and   alcohol  contrary  to  orders  during  the  season  is 
easily  detected,  and  is  dropped  from  the  squad. 
Yours  truly, 

WILLIAM  H.  EDWARDS, 

Capt.  '99  Football  Team, 

PRINCETON  UNIVERSITY. 

We  have  learned  that : 

1.  Muscles  enable  us  to  move. 

2.  Muscles  give  a  pleasing  shape  to  the  body. 

3.  Muscles  can  contract  and  relax. 

4.  Muscles   which    are   fastened   to  bones  pull  on  them  in  contracting, 
and  thus  produce  movement. 

5.  Muscles  contract  because  messages  from  the  brain  come  to  them  along 
nerves. 

6.  Some  muscles  are  voluntary,  others  are  involuntary. 

7.  Muscles  are  made  up  of  fibres. 

8.  Some  muscles  end  in  tendons,  which  are  fastened  to  bones. 

9.  Exercise  makes  muscles  stronger. 

10.  Muscles  can  do  better  work  without  alcohol   and  tobacco  than  with 
them. 


CHAPTER  IV 

THE   FOUR    KINDS    OF   FOOD 

Food  builds  up  the  body. — Everything  wears 
away  as  time  passes.  Your  shoes  wear  out  and  have 
to  be  repaired  with  leather.  Your  warm  winter  stock- 
ings wear  out  and  have  to  be  darned  with  yarn. 
Boys'  shirts  and  girls'  dresses  wear  out  and  have  to  be 
mended  with  cloth. 

Our  bodies,  too,  are  wearing  out  from  day  to  day 
and  have  to  be  repaired, — not  with  leather,  or  yarn, 
or  cloth,  but  with  bread  and  milk,  meat  and  vegeta- 
bles, and  other  things  that  we  eat  and  drink.  Some 
of  your  skin  wears  out  every  day.  If  you  scrape  the 
skin  of  your  arm  gently  with  a  knife,  you  will  collect 
on  it  a  great  many  particles  that  are  just  ready  to  fall 
away.  Even  your  muscles  and  your  brain  wear  out, 
although  you  cannot  see  the  worn-out  particles.  But 
as  each  particle  wears  out  it  is  washed  away  and  a 
new  one  is  made  in  its  place.  The  material  out  of 
which  these  new  particles  are  made  is  obtained  from 
food.  Food  is  any  substance  that  can  be  used  to 
nourish  the  body  without  injuring  it.  Besides  being 
used  for  repair,  food  produces  the  heat  of  the  body? 


46  PHYSIOLOGY   FOR  CHILDREN 

the  case  of  children  some  food  is  used  up  also  in. 
growth. 

Kinds  of  food. — We  must  eat  different  kinds  of 
food  if  we  wish  to  be  strong  and  healthy,  because  no 
one  kind  can  supply  all  the  different  materials  that 
are  needed  to  build  up  every  part  of  the  body  and  to 
furnish  it  with  heat  and  power  to  work.  This  is  the 
reason  why  we  have  several  kinds  of  food  on  our 
tables  for  each  meal.  Sugar  is  a  useful  food,  but 
if  you  ate  sugar  for  breakfast,  dinner,  and  supper, 
day  after  day,  and  ate  nothing  else,  you  would  become 
very  thin  and  weak,  and,  in  the  end,  would  starve  io 
death. 

It  is  easy  to  make  a  long  list  of  different  articles  of 
food  that  are  commonly  used.  Some  of  these  are  beef 
and  mutton,  turkey  and  chicken;  fish  and  oysters, 
potatoes  and  cabbage ;  bread,  butter,  and  eggs ;  pie  and 
cake ;  fruits ;  water,  milk,  tea,  coffee,  cocoa,  and  choco- 
late. This  by  no  means  ends  the  list,  yet  in  spite  of 
the  many  different  articles  that  might  be  named,  there 
are  only  four  different  kinds  of  food,  and  everything 
that  you  eat  belongs  to  one  or  more  of  these  four 
kinds. 

Proteid. — One  of  the  four  kinds  of  food  is  called 
proteid.  This  is  a  strange  name,  yet  you  have  seen 


THE  FOUR  KINDS   OF  FOOD  47 

proteid  many  times.  The  white  of  an  egg  is  one  kind 
of  proteid,  and  is  called  albumen.  Before  it  is  cooked 
it  has  a  clear,  glassy  appearance,  and  is  quite  soft,  like 
thin  jelly.  You  can  see  through  it  very  much  as  you 
can  see  through  glass. 

Muscle — that  is,  lean  meat  of  all  kinds — is  made  up 
largely  of  proteid s.  If  you  should  look  at  a  thin  strip 
of  muscle  through  a  microscope,  you  would  see  the 
clear,  glassy-looking  proteid,  somewhat  like  the  white 
of  an  egg  in  appearance.  Milk  and  cheese  have  much 
proteid  in  them.  Many  vegetables  and  grains  also 
contain  it. 

The  chief  use  of  proteids  is  to  build  up  and  repair 
the  tissues  of  the  body,  but  they  can  also  be  used  to 
produce  heat  and  power  to  work. 

Starch  and  sugar. — Starch  and  sugar  are  another 
of  the  four  kinds  of  food. 

We  may  not  think  that  we  are  eating  starch  when 
we  eat  bread,  cake,  rice,  or  potatoes ;  yet  all  of  them 
contain  much  starch.  It  forms  a  large  part  of  all  grains, 
such  as  wheat,  corn,  oats,  and  rice.  Food  containing 
starch  is  sometimes  called  starchy  food.  Starch  and 
sugar  are  considered  the  same  kind  of  food  because 
after  starch  has  been  eaten  it  changes  into  a  form  of 
sugar. 


48 


PHYSIOLOGY   FOR   CHILDREN 


Here  is  a  picture  showing  how  the  starch  in  wheat 
looks  through  a  microscope.  Each  of  the  little  starch 
grains  is  enclosed  in  a  thin  but  very  tough  envelope. 


-9  Q 


STARCH    GRAINS    IN   WHEAT.       (Magnified.) 


When  starch  is  cooked,  its  grains  swell  up  and  burst 
their  envelopes. 

Below  is  a  picture  of  the  starch  grains  of  a  potato  as 
they  appear  when  seen  through  a  microscope. 

Starchy  food  is  needed  to  produce  heat  and  power  to 
work. 


STARCH  GRAINS  IN  POTATO.   (Magnified.) 


THE   FOUR  KINDS   OF  FOOD 


49 


Fat. — Fat  is  the  third 
kind  of  food.  As  a 
rule,  children  do  not  like 
fat  meat,  but  they  like 
butter,  and  yet  butter 
is  only  fat  obtained 
from  milk.  Here  is  a 
picture  of  a  drop  of 
milk  as  it  looks  through 
a  microscope.  It  shows 

the    fat,     Or     butter,    in      ROUND  PARTICLES  OF  FAT  IN  A  DROP 

little  round  particles.          OF  MILK  SEEN  UNDER  A  M<CROSC0^. 

Fat  also  produces  heat  and  power  to  work. 

Mineral  food. — The  fourth  kind  of  food  is  mineral 
food,  and  consists  of  water  and  salt.  Common  table 
salt  is  a  very  important  food.  You  eat  even  more  of 
this  salt  than  you  think,  for  nearly  every  article  of 
food  contains  it.  It  is  found  in  all  the  fluids  and  tis- 
sues of  the  body.  You  could  not  live  without  it.  In 
his  book,  "In  Darkest  Africa,"  Stanley  tells  of  regions 
where  savages  are  accustomed  to  travel  many  hun- 
dreds of  miles  under  great  difficulties  to  obtain  a  sup- 
ply of  salt.  Many  of  the  lower  animals  also  have  a 
natural  craving  for  it. 

Besides  the  common  salt  that  we  have  on  our  tables 


50  PHYSIOLOGY   FOE   CHILDREN 

there  are  many  other  kinds, — salts  of  lime,  salts  of 
potash,  salts  of  sodium,  salts  of  phosphorus,  salts  of  iron, 
as  well  as  others.  Small  portions  of  some  of  these  salts 
are  contained  in  almost  every  article  of  food  that  we 
eat  or  drink. 

One  use  of  salts  is  to  help  in  making  bone.  The 
hardness  of  bone  is  due  to  the  lime  salts  it  contains. 

Water,  our  natural  drink,  is  also  a  mineral,  and  one 
that  we  cannot  live  without.  We  need  it  to  dissolve 
our  food,  and  also  to  dissolve  and  wash  away  the 
waste  matter.  More  than  half  of  our  body  consists  of 
water.  In  addition  to  that  which  we  drink,  we  get  a 
great  deal  of  water  in  beef,  bread,  potatoes,  and  other 
things  we  eat. 

It  is  a  very  important  matter  to  get  pure  drinking 
water.  If  we  get  it  from  a  well,  the  well  should  be 
kept  thoroughly  clean.  The  ground  around  the  well 
should,  if  necessary,  be  raised  so  as  to  be  higher  than 
the  ground  farther  away.  The  surface  water  will  then 
run  away  from  the  well  instead  of  draining  into  it. 
Every  care  should  be  taken  to  allow  nothing  near  the 
well  which  can  in  any  way  make  the  water  impure. 
Impure  water  may  be  very  injurious,  for  it  may  carry 
germs  of  disease.  Even  water  that  is  clear  and  spark- 
ling may  be  harmful 


THE   FOTJK   KINDS    OF   FOOD  51 


THE  GROUND  AROUND  THE  WELL  SHOULD  BE  HIGHER. 

Many  towns  and  cities  take  their  drinking  water 
from  streams  or  lakes  by  means  of  underground  pipes. 
Every  one  who  lives  on  the  banks  of  such  streams 
should  be  careful  not  to  allow  filth  of  any  kind  to  get 
into  the  water  that  others  are  going  to  drink. 

We  have  learned  that : 

1.  Food  builds  up  the  body  and  repairs  it  as  it  wears  out. 

2.  Food  is  the  fuel  of  the  body  and  keeps  it  warm. 

3.  Food  gives  us  power  to  work. 

4.  We  must  eat  different  kinds  of  food. 

5.  There  are  only  four  kinds  of  food. 

6.  Proteids  build  up  and  repair  the  tissues  of  the  body. 

7.  Starch,  sugar,  and  fat  produce  heat  and  power  to  work. 

8.  Mineral  food  is  needed  to  make  bone. 

9.  The  body  needs  water. 

10.  Water  often  contains  germs  of  disease. 


CHAPTER  V 

DIFFERENT   ARTICLES    OF   FOOD 

The  perfect  food. — Milk  is  a  perfect  food  for  young 
children.  It  is  both  food  and  drink  for  them.  Milk 
consists  of  water,  proteid,  fat,  sugar,  and  salts.  The  fat, 
when  separated  by  churning,  is  called  butter.  What  is 
left  of  the  milk  is  called  buttermilk.  It  contains  all 
of  the  milk  except  the  fat,  and  is  a  useful  food.  The 
fat  and  the  proteid  together  can  be  separated  from 
the  rest  and  made  into  cheese ;  the  water,  sugar,  and 
salts  that  are  left  behind  are  called  whey. 

Milk  must  be  pure  to  be  healthful.  Great  care 
should  be  taken  to  keep  it  clean.  The  stables,  cows, 
and  those  who  do  the  milking  should  be  strictly  clean; 
and  all  vessels  in  which  milk  is  put  should  first  be 
thoroughly  washed  with  boiling  water.  Milk  should 
not  be  kept  in  a  damp,  mouldy  cellar,  but  in  a  clean, 
dry,  well-aired  place. 

Animal  food. — Almost  all  animal  food  is  more 
readily  digested  than  vegetable  food.  Milk,  "the  per- 
fect food,"  is  an  animal  food.  Eggs,  though  hardly  a 
perfect  food — having  too  little  sugar — are  valuable 
articles  of  diet,  for  they  consist  of  proteid,  fat,  and 


DIFFERENT   AETICLES   OF   FOOD  53 

some  mineral  matter.  Usually  they  are  easily  digested 
if  they  are  soft-boiled,  poached,  or  made  into  cus- 
tards. 

Meat  consists  of  water,  proteid,  fat,  and  some  salts. 
Beef,  lamb,  chicken  and  turkey  are  the  most  digestible 
forms  of  meat.  Fresh  fish  also  is  easily  digested,  and 
forms  another  valuable  article  of  diet. 

Vegetable  food. — Such  cereals  as  wheat,  rice,  bar- 
ley, oats  and  rye  consist  of  starch,  proteids,  water, 
salts,  and  fat.  The  most  important  article  of  food 
made  from  cereals  is  bread.  In  this  country  bread  is 
usually  made  from  wheat.  If  the  proteid  part  of  the 
wheat  is  left  in  the  flour  it  will  have  a  brown  color. 
Bread  made  from  this  flour  is  more  nutritious  but  less 
easily  digested  than  bread  made  from  white  flour. 

Potatoes  consist  largely  of  water  and  starch.  They 
are  usually  eaten  with  cream,  butter,  or  gravy  and 
meat,  and  in  this  way  a  supply  of  starch,  fat,  and  pro- 
teid is  obtained.  Green  peas,  string  beans,  spinach, 
and  asparagus  are  examples  of  other  vegetables  that 
are  easily  digested.  Such  vegetables  are  useful  chiefly 
for  the  salts  they  contain. 

Kipe,  sound,  fresh  fruits  are  of  some  value  as  food, 
because  of  the  sugar  and  salts  in  them.  Fruit  salts 
are  especially  good  for  growing  children. 


54  PHYSIOLOGY   FOE   CHILDEEN 

Food  not  easily  digested. — Some  articles  of  food 
are  more  easily  digested  and  more  nutritious  than 
others.  People  have  to  learn  by  experience  what 
agrees  with  them,  and,  if  they  are  wise,  they  will  not 
eat  food  that  disagrees  with  them. 

Pork  of  any  kind,  salt  meats,  salt  fish,  veal,  liver, 
kidney,  goose,  and  duck  are  hard  to  digest. 

Green  corn,  radishes,  raw  celery,  onions,  tomatoes, 
carrots,  and  cucumbers  are  not  easily  digested,  and 
contain  only  a  small  amount  of  nourishment. 

Hot  bread,  buns,  rolls,  and  cake  are  hard  to  digest. 
Pies,  tarts,  pastry,  nuts,  and  salads  are  not  easily  digested. 

Unripe  or  partially  decayed  fruits  should  never  be 
eaten.  Dried,  canned,  and  preserved  fruits,  and  jellies 
are  not  so  desirable  as  fresh  ripe  fruit. 

The  cooking  of  food. — Most  of  our  food  is  cooked 
in  some  way,  in  order  to  make  it  pleasanter  to  the 
taste,  or  easier  to  digest.  After  having  been  cooked, 
meat  is  more  tender,  and  more  digestible.  Only  a 
small  amount  of  uncooked  starch  can  be  digested, 
but  after  starchy  food  has  been  well  cooked  the 
starch  grains  swell  and  burst  their  envelopes,  and  can 
then  be  easily  digested. 

Care  is  needed  in  the  cooking  and  serving  of 
food.  Every  dish  or  utensil  in  which  it  is  cooked, 


DIFFEEENT   ARTICLES    OF   FOOD 


55 


THE    COOKING    <5F    FOOD. 


and  every  dish  in  which  it  is  served  or  put  away, 
should  be  thoroughly  clean.  Pood  should  be  kept 
covered  as  much  as  possible,  to  protect  it  from  insects. 

Every  one  should  learn  to  cook.  Such  knowledge 
is  always  useful,  and  often  necessary. 

Artificial  drinks. — Water  is  often  flavored  in 
different  ways  to  make  artificial  drinks.  All  artificial 
drinks  may  be  divided  into  two  classes,  those  which 
contain  alcohol,  and  those  which  do  not. 

Among  those  which  do  not  contain  alcohol  are 
tea,  coffee,  cocoa,  and  chocolate.  These  drinks  are 


56  PHYSIOLOGY    FOR    CHILDREN 

taken  mainly  because  of  their  pleasant  taste  and 
the  agreeable  effects  they  produce.  Cocoa  and 
chocolate  are  more  nourishing  than  either  tea  or 
coffee,  and  if  prepared  with  plenty  of  milk  may 
be  given  to  children.  Tea  and  coffee  are  not  good 
drinks  for  children,  and  grown  people  are  injured 
by  taking  them  too  strong,  or  in  too  large  a  quan- 
tity. 

Rules. — A  few  simple  rules  in  regard  to  eating 
should  always  be  observed. 

1.  We  should  eat  slowly  and  chew  our  food  well. 

2.  Food  should  not  be  eaten  after   the  feeling  of 
hunger  is  satisfied. 

3.  Meals  should  be  taken  at  regular  hours. 

4.  Nothing  should  be  eaten  between  meals. 

5.  The  evening  meal  should  be   the  simplest    and 
plainest  meal  of  the  day. 

6.  No   drink  should  be  taken  while  there  is  food 
in  the  mouth. 

7.  Ice   water   should  not  be  taken  freely  at   meal 
time. 

Alcohol. — In  our  choice  of  what  we  eat  and  drink 
we  should  select  what  will  keep  the  body  in  as  nearly 
perfect  condition  as  possible,  and  avoid  what  will 
prevent  us  from  doing  our  best  work.  The  use  of 


DIFFEEENT   AETICLES    OF   FOOD  57 

alcoholic  liquor  unfits  a  man  for  careful  and  exact 
work,  and  for  holding  positions  in  which  he  has  charge 
of  the  life  and  property  of  others.  Many  companies 
and  business  firms  will  not  employ  a  man  who  is 
known  to  drink,  because  they  are  afraid  to  trust  their 
business  to  him.  The  following  show  that  this  state- 
ment is  true: 

WESTINGHOUSE   ELECTRIC   &   MANUFACTURING   COMPANY, 
PITTSBURG,  PA. 

January  15,  1900. 

Gentlemen: — Replying  to  yours  of  the  13th  instant,  we  do 
not  post  or  publish  any  rules  concerning  the  use  of  alcoholic 
liquors  by  our  employees,  nor  do  we  consider  such  rules  at  all 
necessary.  We  do  not  knowingly  employ  for  any  important 
position  any  person  known  to  be  a  habitual  user  of  alcoholic 
liquors.  If  we,  unfortunately,  find  such  a  person  in  our 
employ,  we  dismiss  him. 

Yours  truly, 

B.  H.  WARREN, 

Second  Vice- President. 

NEW  YORK  CENTRAL  &  HUDSON  RIVER  R.  R.  Co. 
"  The  use  of  intoxicating  drink  on  the  road  or  about  the 
premises  of  the  corporation  is  strictly  forbidden.     No  one  will 
be  employed,  or  continued  in  employment,  who  is  known  to  be 
in  the  habit  of  drinking  intoxicating  liquor/7 

E.  VAN  ETTEN, 

General  Superintendent. 


58  PHYSIOLOGY   FOE   CHILDREN 

ILLINOIS  CENTRAL  EAILKOAD  COMPANY. 
' '  The  Company  hereby  announces  that  in  employment  and 
promotions  in  its  service  a  preference  will  be  given  to  persons 
who  are  known  to  be  total  abstainers  ;  and  under  no  circum- 
stances will  it  tolerate  acts  of  drinking  by  men  on  duty,  or 
wearing  any  part  of  the  Company's  uniform." 

A.  W.  SULLIVAN, 

General  Superintendent. 

METROPOLITAN  STREET  KAILWAY  COMPANY,  NEW  YORK. 

"  Drinking  any  beer,  wine,  liquor  or  intoxicating  drink,  or 
entering  any  drinking  place  during  the  hours  of  duty,  or  the 
carrying  of  any  intoxicating  drink  about  the  person,  or  the 
bringing  of  same  on  the  premises  of  the  Company  will  be  cause 
for  discharge. 

The  frequenting  of  drinking  places,  or  the  indulgence  to 
excess  in  intoxicating  liquors  when  oil  duty,  will  be  cause  for 
discharge/' 

OREN  ROOT,  JR., 

Assistant  to  the  President. 

CANADIAN  PACIFIC  RAILWAY  COMPANY. 
<fln  the  interests  of  safety  and  efficiency,  the  use  of  intox- 
icants while  on  duty  is  absolutely  prohibited.  No  instance  of 
intoxication  on  duty  will  ever  be  overlooked,  but  will  be  fol- 
lowed by  immediate  dismissal.  The  habitual  use  of  intoxicating 
liquors  will  be  considered  sufficient  cause  for  dismissal,  and 
preference  will  in  every  case  be  given  to  those  who  abstain 
from  their  use." 

J.  W.  LEONARD, 

General  Superintendent. 


DIFFEKENT  AKTICLES   OF   FOOD 


59 


MEN   WHO   HAVE   CHARGE   OF   THE    LIVES   OF   OTHERS. 

AMERICAN  EXPRESS  COMPANY. 

"Any  employee  drinking  liquor  while  on  duty,  or  during 
business  hours,  will  be  cautioned  once,  and  if  he  repeats  the 
offence,  be  discharged  immediately.  Any  employee  who  is 
known  to  drink  to  excess,  while  off  duty,  will  be  dismissed 
from  the  service." 

JAS.  C.  FARGO, 

President. 

We  have  learned  that : 

1.  Milk  is  a  perfect  food. 

2.  Meat  contains  proteids,  fat,  salts,  and  water. 

3.  Cereals  contain  water,  salts,  starch,  and  proteids. 

4.  Vegetables  are  useful  chiefly  for  the  salts  they  contain. 

5.  Some  articles  of  food  are  not  easily  digested. 


CHAPTER  VI 

HOW    OUR    FOOD    IS    CHANGED    INTO    BLOOD 

Digestion. — The  leather  that  is  used  to  make  your 
shoes  was  once  the  skin  of  an  ox  or  a  calf ;  the  yarn 
of  which  your  winter  stockings  are  made  was  once 
growing  as  wool  on  the  back  of  a  sheep ;  the  cotton 
that  is  used  to  make  thread  and  cloth  was  once  grow- 
ing in  the  fields  of  the  sunny  South.  Before  skin, 
wool,  and  cotton  can  be  used  to  make  or  repair  our 
clothing  they  have  to  be  changed,  and  this  changing 
is  done  in  buildings  which  we  call  factories. 

The  soft,  fluffy  cotton  carried  into  a  factory  is 
changed  to  a  piece  of  cloth ;  the  wool  is  changed  into 
yarn,  and  the  skin  of  the  ox  or  the  calf  is  changed 
into  leather. 

Just  so,  everything  you  eat  must  be  changed  before 
it  can  be  used  to  build  up  or  repair  the  body ;  it  must 
be  changed  into  blood ;  and  the  first  steps  of  this  pro- 
cess of  changing  are  called  digestion. 

The  factory  in  which  digestion  is  carried  on  is  a 
long  tube  which  passes  through  the  body.  In  it 
there  are  three  main  workshops,  the  mouth,  the 
stomach,  and  the  intestine. 


HOW    OUK   FOOD   IS   CHANGED   INTO   BLOOD 


61 


The  process  of  digestion 
begins  in  the  mouth,  where 
our  sharp  front  teeth  cut  off 
pieces  of  food;  our  broad 
back  teeth  grind  the  food  up  ; 
and  the  tongue  rolls  it  around 
so  that  it  may  be  well  chewed 
and  mixed  with  saliva. 

The  teeth.—  The  teeth  are 
made  of  material  which  re- 
sembles bone.  Every  tooth 
has  a  crown,  which  is  the  part 
you  can  see  in  the  mouth,  and 
a  root  or  roots  which  fit  into 
holes  in  the  jaw.  If  you 
crack  a  tooth  with  a  hammer 
you  will  find  in  the  centre  a 
little  hollow  for  small  nerves 
and  blood  tubes. 

The  crown  of  each  tooth  is 
covered  with  a  thin  layer  of 
enamel,  the  hardest  material 
in  the  body.  If  a  part  of  the 
enamel  is  broken  off,  the  tooth 
will  decay  and  a  hole  will  be 


*,  the  esophagus. 

s,  the  stomach. 


A  SECTION 
OF  A  TOOTH, 
SHOWING 
ENAMEL, 
CROWN,  CAV- 
ITY AND 
ROOTS. 


62  PHYSIOLOGY   FOE   CHILDEEN 

formed.     This  becomes  larger  and  ]arger  until  a  nerve 
is  reached,  and  then  the  tooth  may  ache. 

We  have  during  our  lifetime  two  sets  of  teeth. 
The  first  teeth  begin  to  come  when  we  are 
about  seven  months  old.  They  are  quite 
small,  and  are  sometimes  called  milk-teeth. 
There  are  only  twenty  of  them.  When  a 
child  is  about  six  years  old  the  roots  of  the 
OFT-TOOTH',  milk-teeth  waste  away,  and  new  teeth,  which 
ENAMEL,  have  been  formed  at  the  roots  of  the  old 
ones,  push  through  the  gums  and  force  the 
old  teeth  out.  These  second  teeth  are  larger 
than  the  milk-teeth.  There  are  thirty-two  of  them  in 
all,  but  four  of  them  do  not  appear  until  we  are  grown 
up,  and  for  this  reason  they  are  called  wisdom-teeth. 

You  should  take  great  care  of  your  teeth  to  prevent 
them  from  decaying.  They  should  be  cleaned  with  a 
soft  brush,  warm  water,  and  a  little  tooth-soap,  or 
tooth-powder,  free  from  grit.  Particles  of  food  should 
not  be  allowed  to  remain  between  the  teeth,  but 
should  be  removed  after  leaving  the  table.  They 
should  not,  however,  be  removed  with  a  pin  or  any- 
thing hard,  but  with  a  bit  of  silk  or  a  piece  of  soft 
wood.  You  should  not  crack  nuts  with  your  teeth, 
or  bite  anything  very  hard,  because,  in  that  way,  the 


HOW  OUE  FOOD  IS  CHANGED  INTO  BLOOD 


THE    SALIVARY  GLANDS,    a,    6,    AND    C. 

enamel  may  be  injured  and  the  teeth  may  soon 
decay. 

The  saliva.— If  you  put  a  piece  of  dry  bread  into 
your  mouth  and  chew  it,  the  bread  soon  becomes 
moist  and  easy  to  swallow.  It  is  moistened  by  a 
watery  fluid,  called  saliva,  which  is  made  in  small 
organs,  called  salivary  glands. 

Glands  are  clusters  of  cells  which  are  held  together 
by  connective  tissue  and  are  surrounded  by  small 
blood  tubes.  These  cells  take  certain  materials  out 


64  PHYSIOLOGY   FOR   CHILDREN 

of  the  blood  into  themselves  and  change  them  into 
new  fluids,  which  are  poured  out  as  they  are  needed. 
Thus,  in  the  salivary  glands,  saliva  is  made  from 
material  taken  from  the  blood.  Besides  the  salivary 
glands,  there  are  other  glands  in  other  parts  of  the 
body. 

From  the  salivary  glands  the  saliva  flows  into  the 
mouth  through  small  tubes.  When  you  have  nothing 
in  your  mouth,  the  salivary  glands  work  slowly,  and 
only  enough  saliva  is  made  to  keep  the  mouth  moist. 
But  the  moment  you  begin  to  eat,  or  chew  anything, 
they  begin  to  work  faster  and  pour  saliva  into  the 
mouth  more  rapidly.  Even  the  sight  or  thought  of 
pleasant  food  will  often  increase  the  flow  of  saliva, 
and,  as  we  say,  "make  the  mouth  water." 

Saliva  Las  the  power  to  change  starch  into  a  kind 
of  sugar.  This  is  very  important,  because  sugar  will 
dissolve  in  water,  but  starch  will  not.  If  you  put 
some  sugar  into  a  cup  of  water,  it  will  dissolve  quickly. 
Stir  the  water  for  a  minute  or  two,  then  pour  it  off, 
and  you  will  find  no  sugar  left  in  the  cup.  If  you  now 
crumble  a  small  piece  of  bread,  which  consists  largely 
of  starch,  and  put  the  crumbs  into  a  cup  of  water, 
they  will  not  dissolve.  When  you  pour  off  the  water 
the  bread  crumbs  will  remain  at  the  bottom  of  the  cup. 


HOW    OUB  FOOD    IS    CHANGED   INTO   BLOOD 


65 


The  starch  in  our  food  must  be  changed  to  sugar  so 
that  it  will  dissolve,  because  it  cannot  make  blood  until 
it  is  dissolved.  We  ought,  therefore,  to  eat  slowly  and 
chew  our  food  well,  so  that  the  starch  in  it  may  be 
well  mixed  with  the  saliva,  which  changes  it  to  sugar. 


THE    PARTS    OF    THE    MOUTH    IN 
BREATHING. 


THE    SAME    PARTS    IN   SWAL- 
LOWING. 


n,  the  nasal  cavity  ;  r,  roof  of  the  mouth  ;  p,  soft  palate  ;  I,  lid  over  opening  into  windpipe  ; 
w,  windpipe  ;  e,  esophagus  ;  t,  tongue  ;  f ',  tooth  ;  f,  food  that  is  being  swallowed. 

(Landois  and  Stirling.) 

The  .chewing  of  tobacco  not  only  wastes  saliva,  but 
is  an  unclean  habit.  Smoking,  too,  wastes  saliva. 

Swallowing.— After  the  food  has  been  torn  to  pieces 
by  the  teeth  and  moistened  by  the  saliva,  the  soft,  wet 
mass  is  pushed  back  into  the  throat  by  the  tongue,  and 
then  passes  through  a  tube,  called  the  esophagus,  into 
the  stomach. 


66 


PHYSIOLOGY   FOR   CHILDREN 


The  wall  of  the  esophagus  contains  muscles.   When 
food   passes   into   this   tube   from   the   mouth    these 


STOMACH  IN  ITS  NATURAL  POSITION. 
(See  Appendix  for  Key.) 


muscles  contract  and  force  the  food   along  until   it 
reaches  the  stomach. 


HOW  OUR  FOOD  IS  CHANGED  INTO  BLOOD 


67 


Before  the  food  can  pass  down  the  esophagus  it  has 
to  pass  over  the  opening  into  the  windpipe.  Some  of 
the  food  might  get  into  the  windpipe  if  it  were  not  for 
a  lid  which  shuts  down  and  covers  the  small  opening 
whenever  we  attempt  to  swallow.  Just  as  soon  as  the 
food  has  passed  the  opening,  the  lid  lifts  up  and  allows 
air  to  go  down  again  into  the  lungs. 

Sometimes  a  crumb,  or  a  drop  of  water,  goes  the 
wrong  way  and  slips  under  this  lid  into  the  windpipe. 
We  then  cough  violently  to  get  it  up.  If  a  large  piece 
of  food  were  to  get  into  the  windpipe  we  should 
die  unless  it  were  quickly 
taken  out,  for  we  could  not 
breathe. 

Digestion  in  the  stom- 
ach.—  The  stomach  looks 
like  a  bag  or  pouch.  Its 
walls  are  made  of  muscle, 
and  have  a  soft  lining  like 
velvet.  The  stomach,  then, 
is  a  muscular  sac  with  a  soft 
lining.  It  lies  in  the  upper 
part  of  the  abdomen,  largely 
to  the  left  side  and  below 
the  heart.  Its  size  varies  A  GASTRIC  GLAND.  (Magnified.) 


68  PHYSIOLOGY   FOR   CHILDREN 

in  different  individuals.  Its  length,  when  fully  dis- 
tended with  food,  is  about  ten  or  eleven  inches,  and 
its  diameter  is  from  four  to  five  inches. 

The  stomach  has  an  opening  at  its  upper  end,  where 
food  comes  into  it  from  the  esophagus,  and  another 
opening  at  its  lower  end,  where  food  goes  out  into  the 
intestine. 

After  food  comes  into  the  stomach  it  is  mixed  with 
a  juice  called  gastric  juice.  Gastric  is  a  word  meaning 
"of  the  stomach,"  so  gastric  juice  simply  means  juice 
of  the  stomach.  The  whole  of  the  soft  lining  of  the 
stomach  is  full  of  liu_  glands  which  make  this  juica 
On  page  67  there  is  a  sketch  of  one  of  these  glands. 
It  is  made  much  larger  than  the  glands  really  are, 
that  you  may  see  \vhat  they  are  like.  When  no  food 
is  in  the  stomach  the  glands  are  at  rest,  but  when 
food  comes  in  they  begin  to  make  gastric  juice  at 
once,  and  pour  it  out  into  the  stomach. 

Gastric  juice  has  the  power  to  dissolve  the  proteid 
part  of  our  food,  such  as  lean  meat,  white  of  egg,  and 
part  of  milk  and  vegetables.  It  cannot  dissolve  starch 
or  fat,  and  it  stops  the  action  of  saliva. 

Soon  after  food  has  been  swallowed,  the  muscles  at 
one  end  of  the  stomach  contract,  making  that  end 
smaller.  This  forces  the  food  to  the  other  end.  Then 


HOW  OUR  FOOD  IS  CHANGED  INTO  BLOOD      69 

the  muscles  at  that  end  contract,  while  the  first  ones 
relax,  and  the  food  is  forced  back  again.  As  the 
food  is  kept  moving  from  one  end  of  the  stomach  to 
the  other,  it  is  mixed  with  the  gastric  juice,  and  the 
mixing  goes  on  until  this  juice  has  completed  its 
work. 

The  food,  however,  does  not  all  remain  in  the 
stomach  until  digestion  there  is  finished.  As  soon  as 
any  part  of  it  is  ready,  it  is  squeezed  out  through  the 
lower  opening  into  the  intestine. 

A  small  part  of  the  food  is  absorbed  into  the  blood 
directly  from  the  stomach  without  passing  into  the 
intestine.  It  soaks  through  the  soft  lining  of  the 
stomach  into  the  blood  tubes  in  its  walls,  and  so 
becomes  a  part  of  the  blood  stream. 

Digestion  in  the  intestine.  —  The  intestine  is  a 
tube  which  extends  downward  from  the  stomach. 
The  upper  part  is  small  in  diameter  and  is  called  the 
small  intestine.  The  lower  part,  which  is  a  continua- 
tion of  the  small  intestine,  is  larger  in  diameter,  and  is 
called  the  large  intestine.  The  small  and  the  large 
intestine  together  are  about  twenty-five  or  thirty  feet 
long,  and  are  nicely  folded  up  in  the  abdomen  so  as  to 
take  up  very  little  room.  The  wall  of  the  intestine  is 
made  up  largely  of  muscle,  arid  has  a  soft  lining  like 


70  PHYSIOLOGY   FOR   CHILDREN 

the  lining  of  the  stomach.  Digestion  in  the  intestine 
takes  place  mainly  in  the  small  intestine. 

In  the  mouth,  part  of  the  food  is  changed  by  a 
fluid,  the  saliva.  In  the  stomach,  another  part  of  the 
food  is  changed  by  a  fluid,  the  gastric  juice.  In  the 
small  intestine,  food  is  changed  by  three  fluids.  One 
of  these,  the  pancreatic  juice,  is  made  by  the  pancreas  ; 
another,  the  bile,  is  made  by  the  liver;  and  the  third, 
the  intestinal  juice,  is  made  in  the  wall  of  the  intestine. 

The  pancreas,  or  sweetbread,  is  a  gland  which  lies 
behind  the  stomach.  It  makes  the  most  wonderful 
fluid  of  all,  the  pancreatic  juice.  The  pancreatic 
juice  can  do  what  saliva  does,  for  it  can  change  starch 
to  sugar.  It  can  do  what  gastric  juice  does,  for  it 
can  digest  proteids.  And  it  can  do  what  neither 
saliva  nor  gastric  juice  can  do, — it  can  digest  fat. 

The  liver  is  the  largest  gland  in  the  body.  It  lies 
in  the  upper  part  of  the  abdomen,  on  the  right  side, 
and  close  to  the  lower  ribs.  It  is  made  up  of  liver 
cells  and  blood  tubes,  held  together  by  connective  tis- 
sue. These  cells  take  from  the  blood  certain  material, 
and  with  it  make  a  bitter  fluid,  called  bile.  The  liver 
is  making  bile  all  the  time,  but  this  fluid  passes  into 
the  intestine  only  when  digestion  is  going  on.  When 
digestion  is  not  going  on,  the  bile  is  stored  in  a  little 


HOW  OUE  FOOD  IS  CHANGED  INTO  BLOOD     71 

pear-shaped  bag,  the  gall  bladder,  which  is  tucked 
away  under  the  liver.     The  bile  does  not,  by  itself, 


THE  LIVER  AND  PANCREAS. 
(See  Appendix  for  Key.) 


digest  food,  but  it  helps  the  pancreatic  juice  to  do  so. 
The  intestinal  juice  is  made  by  small  glands  in  the 
soft  lining  of  the  intestine.     Its  power  to  digest  food 


72  PHYSIOLOGY   FOR   CHILDREN 

is  very  slight.  Its  most  important  use  is  to  assist  in 
the  digestion  of  starch  and  cane  sugar. 

When  the  food  enters  the  small  intestine  from  the 
stomach  much  of  it  is  still  undigested.  It  then  meets 
the  bile  and  the  pancreatic  juice.  These  fluids,  com- 
ing from  the  pancreas  and  the  liver,  enter  the  intestine 
by  a  small  tube  near  the  place  where  the  food  enters 
from  the  stomach.  The  muscles  in  the  wall  of  the 
intestine  contract  and  force  the  food  along  in  the  in- 
testine, so  that  it  becomes  mixed  with  the  pancreatic 
juice,  the  bile,  and  the  intestinal  juice. 

By  the  combined  action  of  these  juices  any  starch 
that  escaped  digestion  in  the  mouth  is  changed  to 
sugar,  any  proteid  that  escaped  digestion  in  the  stomach 
is  digested,  and  the  fats  upon  which  the  saliva  and 
gastric  juice  have  no  power  are  also  digested.  Water 
is  not  digested,  for  it  does  not  require  to  be  changed, 
and  salt  is  dissolved  but  not  changed. 

As  a  result  of  the  changes  brought  about  by  diges- 
tion, the  food  which  was  swallowed  as  bread,  butter, 
meat,  potatoes,  milk,  water,  salt,  and  so  on,  becomes 
a  milk-like  liquid  in  the  intestine.  The  nourishing 
part  of  the  food  contained  in  this  milk-like  liquid  is 
now  ready  to  be  taken  into  the  blood  tubes  and 
become  blood. 


HOW    OUK   FOOD   IS   CHANGED   INTO   BLOOD  73 

How  food  is  taken  into  Mood  tubes. — You  will 
remember  that  the  intestine  has  a  lining  which  is  soft 
like  velvet.  The  surface  of  this  soft  lining  in  the  small 
intestine  has  little  tongue-like  projections.  One  of 
these  little  projections  is  called  a  villus,  while  villi  is 
the  name  given  to  more  than  one.  There  are  about 
four  million  villi  in  the  small  intestine,  but  there  are 
none  in  the  large  one. 

In  each  of  these  villi  there  are  very  small  blood  tubes, 
and  also  one  or  more  little  tubes  called  lacteals.  The 
word  lacteal  means  like  milk,  and  this  name  is  given 
to  the  tubes  because  they  contain  a  fluid  which  looks 
like  milk. 

As  food  is  digested  in  the  intestine  it  soaks,  or 
oozes,  through  the  walls  of  the  villi.  The  proteids, 
sugar,  and  mineral  part  of  the  food  then  pass  on 
through  the  walls  of  the  little  blood  tubes,  mix  with 
the  blood,  and  go  with  it  from  these  little  tubes  into 
larger  ones  called  veins. 

The  digested  fats  do  not  pass  through  the  walls 
of  the  little  blood  tubes  of  the  villi,  but  go  through 
the  walls  of  the  lacteals.  In  the  lacteals  the  digested 
fats  have  the  appearance  of  a  milky  fluid.  The 
lacteals  pass  through  a  number  of  tiny  glands,  and 
unite  again  and  again  to  form  larger  tubes.  These 


74 


PHYSIOLOGY   FOE  CHILDREN 


larger  tubes  finally  unite  to  make 
one  tube  about  the  size  of  a  goose 
quill,  or  a  small  lead  pencil,  and 
this  pours  its  contents  into  a  large 
vein  to  mix  with  the  blood. 

Alcoholo — Alcohol  makes  the 
small  blood  tubes  in  the  lining  of 
the  stomach  larger,  and  they  then 
contain  a  greater  amount  of  blood 
than  usual.  This  gives  a  reddish 
appearance  to  the  lining  of  the 
stomach,  just  as  a  mustard  plaster 
will  cause  a  reddish  appearance  of 
the  skin.  If  only  a  small  amount 
of  alcohol  is  taken,  the  blood  tubes  are  enlarged  for  a 
short  time,  and  then  return  to  their  usual  size. 

The  chief  danger  in  drinking  a  small  amount  of 
alcoholic  liquor  occasionally  is  not  in  an  immediate 
injury  to  the  stomach,  or  any  other  organ,  but  in  the 
fact  that  this  drinking  of  small  amounts  leads  so  often 
to  the  drinking  of  larger  amounts  which  are  harmful, 
and  to  the  forming  of  a  habit  of  drinking  which  cannot 
be  given  up,  even  when  a  man  knows  that  alcoholic 
liquor  is  injuring  him.  It  is  easy  to  see,  therefore,  that 
the  only  safe  plan  is  not  to  drink  alcoholic  liquors. 


HOW   OUK  FOOD   IS    CHANGED   INTO   BLOOD  75 

If  alcoholic  liquor  is  taken  frequently,  even  in 
moderate  quantities,  the  blood  tubes  in  the  lining  of 
the  stomach  are  kept  large,  and  thus  the  lining  con- 
tinues to  be  inflamed.  The  gastric  juice  is  less  able 
to  do  its  work,  and  digestion  in  the  stomach  requires 
more  time  than  it  should. 

When  large  amounts  of  alcohol  are  taken  for  a 
length  of  time  the  extreme  inflammation  of  the  lining 
of  the  stomach  causes  a  serious  disease,  and  in  the  end 
it  may  become  impossible  for  the  stomach  to  retain 
and  digest  food. 

The  large  amount  of  liquid  that  is  often  taken  by 
beer  drinkers  stretches  the  wall  of  the  stomach  and 
greatly  increases  its  size.  This  stretching  weakens  the 
muscles  in  the  wall  of  the  stomach,  so  that  food  is  not 
forced  on  into  the  intestine  so  promptly  as  it  should 
be.  This  is  a  frequent  cause  of  painful  indigestion. 

Effect  of  alcohol  on  the  liver. — When  alcohol  is 
swallowed  it  quickly  soaks  through  the  soft  lining  of 
the  stomach  into  the  blood  tubes  in  its  wall,  and  then 
goes  with  the  blood  to  the  liver.  The  liver  is,  there- 
fore, the  first  organ  to  receive  the  alcohol  after  it 
enters  the  blood. 

Alcohol  is  particularly  injurious  to  the  cells  of  the 
liver,  and  is  the  chief  cause  of  a  disease  of  the  liver 


76  PHYSIOLOGY   FOR   CHILDREN 

which  often  proves  fatal.  In  this  disease  the  liver 
becomes  larger  than  it  should  be.  It  may  afterwards 
partly  waste  away  and  have  a  shriveled,  hardened 
appearance.  It  is  then  commonly  called  a  "  hob-nailed 
liver." 

Effect  of  tobacco  on  digestion. — The  continued 
use  of  tobacco,  especially  if  much  is  used,  often  inter- 
feres with  digestion.  When  it  is  used  by  young 
persons  it  tends  to  hinder  growth,  because  it  prevents 
the  proper  nourishing  of  the  body. 

Jay  W.  Seaver,  M.  D.,  Director  of  the  Yale  Uni- 
versity gymnasium,  proved  that  the  use  of  tobacco 
has  this  effect.  At  different  times,  he  made  measure- 
ments of  students  to  learn  how  much  they  had  grown, 
and  he  found  that  the  average  growth  of  those  who 
did  not  use  tobacco  was  considerably  greater  than 
the  average  growth  of  those  who  did  use  it. 

We  have  learned  that : 

1.  Food  must  be  changed  into  blood  before  the  body  can  use  it. 

2.  This  change  begins  in  the  mouth,  and  is  completed  in  the  stomach  and 
the  intestine. 

3.  In  the  mouth,  food  is  chewed  and  mixed  with  saliva. 

4.  Our  teeth  cut  and  grind  the  food  into  small  pieces. 

5.  Saliva  moistens  the  food,  and  changes  starch  to  a  kind  of  sugar. 

6.  From  the  mouth,  food  passes  through  the  esophagus  to  the  stomach 

7.  A  little  lid  keeps  food  from  getting  into  the  windpipe. 


HO\Y   OUR  FOOD   IS    CHANGED   INTO   BLOOD  77 

8.  In  the  stomach,  food  is  changed  by  gastric  juice. 

9.  Gastric  juice  can  dissolve  proteid  food. 

10.  In  the  intestine,  food  is  changed  by  bile,  pancreatic  juice,  and  intes- 
tinal juice. 

11.  Bile  assists  the  pancreatic  juice,  which  can    dissolve  starch,  proteid 
and  fat. 

12.  Bile  is  made  in  the  liver,  and  pancreatic  juice  in  the  pancreas. 

13.  When   food   is  digested,    it   is  taken  up    by   little   veins   and   other 
small  tubes,  called  lacteals,  in  the  wall  of  the  intestine,  and  mixed  with 
the  blood. 


CHAPTER  VII 

HOW  THE  BLOOD  BUILDS  UP  THE  BODY 

The  blood  carries  food  for  the  body. — After 
leather,  yarn,  and  cloth  are  manufactured  they  are 
not  stored  away  and  locked  up  in  factories,  but  are 
sent  out  over  the  country  by  railroads,  canals,  and 
rivers  to  cities,  towns,  and  villages,  so  that  the  people 
who  need  them  can  find  and  use  them. 

In  the  same  way,  after  our  food  is  manufactured 
into  blood  it  does  not  remain  in  the  factory,  but,  is 
sent  out  to  all  parts  of  the  body,  so  that  it  can  be 
used  in  building  them  up  and  repairing  them. 

Instead  of  railroads,  canals,  and  rivers  we  have 
running  through  our  bodies  a  system  of  little  tubes ; 
and  instead  of  railroad  trains  and  canal  boats  we 
have  the  warm,  red  blood  flowing  through  these 
tubes,  loaded  with  material  the  body  needs  to  build 
it  up.  In  your  chest  is  the  heart,  a  muscular  pump, 
which  works  without  ceasing  day  and  night  as  long 
as  you  live,  and  forces  the  blood  through  all  of 
the  blood  tubes,  even  to  the  very  tips  of  your  fingers 
and  toes. 

The   arteries.— There   is   a  large  blood  tube,  the 


HOW    THE   BLOOD   BUILDS   UP  THE   BODY 


79 


aorta,  into  which  blood  comes  out  from  the  heart. 
You  know  how  branches  are  given  off  from  the  trunk 
and  larger  limbs  of  a  tree.  The  aorta  also  gives  off 


HEART  AND    AORTA. 


a,  Branches  of  Aorta. 

branches  almost  at  its  very  beginning,  and  all  along 
its  course.  Each  of  these  branches  divides  again  and 
again  into  smaller  ones,  and  the  name  arteries  is  given 
to  the  aorta  and  its  larger  branches,  through  which 


80  PHYSIOLOGY   FOK   CHILDEEN 

the  blood  flows  out  from  the  hearfc  to  all  parts  of  the 
body. 

The  capillaries.— This  dividing  of  the  arteries 
goes  on  until  the  little  blood  tubes  are  so  small  that 
you  cannot  see  them,  and  they  are  then  called  capilla- 
ries. There  are  so  many  of  these  capillaries,  and  they 
lie  so  closely  together  that  you  cannot  put  the  point 
of  a  needle  between  them.  If  you  pierce  your  skin 
with  a  needle,  its  point  will  pass  through  one  or  more 
tiny  capillaries  and  allow  the  blood  to  flow  from  them. 

The  veins.— After  flowing  through  the  capillaries, 
the  blood  commences  to  return  to  the  heart,  and  the 
tubes  through  which  it  returns  are  called  veins.  You 
have  seen  little  rills  on  a  hillside  unite  to  make  a  larger 
stream,  and  you  know  that  larger  streams  unite  to 
make  one  still  larger,  until  a  great  river  is  formed. 
In  a  similar  way,  these  tiny  capillaries  unite  to  make 
small  veins,  and  these  small  veins  unite  to  make  larger 
ones,  until  all  the  veins  from  the  lower  part  of  the 
body  have  joined  to  form  one  large  vein  through 
which  the  blood  flows  back  to  the  heart.  All  the 
capillaries  and  veins  of  the  upper  part  of  the  body 
unite  in  the  same  way  to  form  another  large  vein 
through  which  the  blood  flows  back  to  the  heart. 

You  have  only  one  body ;  but  different  parts  of  it, 


HOW   THE   BLOOD   BUILDS   UP   THE   BODY  81 

such  as  the  head,  the  arms,  the  hands,  have  different 
names.  There  is  only  one  set  of  blood  tubes,  but 
one  part  of  it  is  called  arteries,  another  part  capil- 
laries, and  a  third  part  veins. 

If  you  start  at  one  point  in  a  circle  and  follow  the 
circumference  you  will  come  round  to  the  point  from 
which  you  started.  The  blood  starts  from  the  heart, 
goes  through  the  body,  and  comes  back  to  the  heart 
very  much  as  if  it  were  moving  in  a  circle.  For  this 
reason  it  is  said  to  circulate  through  the  body. 

What  takes  place  in  the  capillaries. — The  walls 
of  the  capillaries  are  very  thin,  thinner  than  the  thin- 
nest paper  you  ever  saw.  While  the  blood  is  flowing 
through  the  capillaries,  the  food  in  the  blood  oozes 
through  the  walls  of  the  capillaries  and  feeds  the  tis- 
sues around  them. 

Oxygen  is  one  of  the  gases  of  which  air  is  com- 
posed. As  the  blood  flows  through  the  lungs  it 
gets  oxygen  from  the  air  we  breathe.  This  oxygen 
is  carried  by  the  blood  to  all  parts  of  the  body, 
and  afterwards  goes  out  through  the  walls  of  the 
capillaries  to  the  tissues,  just  as  food  passes  out  to 
the  tissues.  While  these  are  going  out  from  the 
blood,  waste  matter,  made  by  the  using  up  of  the 
food  and  the  wearing  out  of  the  tissues,  comes  into 
6 


PHYSIOLOGY   FOR   CHILDREN 


the  blood  from  the  tissues,  th rough,  the  walls  of  the 
capillaries. 

This  exchange  between  the  blood  and  the  tissues 
takes  place   only  in   the  capillaries  and  not   in  the 


ARTERY,    CAPILLARIES,   AND    VEIN. 

(Magnified.) 

arteries  or  veins.  The  walls  of  the  arteries  and 
veins  are  too  thick  to  let  the.  food  and  oxygen  go 
out  or  the  waste  matter  come  in.  In  the  arteries 
the  blood  simply  flows  out  to  the  capillaries  from  the 
heart,  and  in  the  veins  it  simply  flows  back  from  the 
capillaries  to  the  heart. 

You  have  now  learned  three  things  which  the  blood 
does   as  it    circulates  through  the  body.      It  brings 


HOW  THE  BLOOD  BUILDS  UP  THE  BODY 


83 


*• 


food  to  the  tissues,  it  brings  oxygen  to  the  tissues,  and 
it  carries  away  matter  that  is  worn  out  and  useless. 

AVhat  the  blood  is  like. — When  the  blood  flows 
from  a  cut  in  your  finger  it  appears  to  be  simply  a 
red  fluid,  but  it  does  not  long  remain  fluid.  It  soon 
becomes  sticky,  and  in  a  few  minutes  thickens  into  a 
mass  which  resembles  jelly.  This  jelly-like  mass  is 
called  a  clot. 

It  is  a  good  thing  for  us 
that  blood  clots,  for  if  it 
did  not  it  would  be  diffi- 
cult, or  impossible,  to  stop 
bleeding,  even  from  a  small 
cut  or  wTourid.  The  clot  is 
nature's  plug  to  stop  bleed- 
ing. 

The  blood  corpuscles.— If  you  should  look  at  a 
drop  of  blood  under  a  microscope  you  would  see  a 
large  number  of  tiny  bodies,  called  corpuscles,  floating 
about.  These  corpuscles  float  in  a  watery  fluid  and 
are  so  small  that  they  cannot  be  seen  without  the 
microscope.  They  are  of  two  kinds,  red  and  white. 

The  red  corpuscles. — The  red  corpuscles  are  tiny 
disks,  flat,  soft,  and  round,  and  are  of  great  use  to  us, 
although  they  are  so  very  small.  The  real  business  of 


RED    AND    WHITE    CORPUSCLES. 

(Magnified.) 


84  PHYSIOLOGY   FOE  CHILDEEN 

these  little  things  is  to  cany  oxygen,  which  they  get 
in  the  lungs  from  the  air  we  breathe.  They  float 
along  in  the  blood  stream,  and,  as  they  are  passing 
through  the  capillaries,  oxygen  escapes  from  them  and 
goes  through  the  walls  of  the  capillaries  to  the  tissues. 

Color  of  the  blood. — The  color  of  the  blood  is 
due  to  its  red  corpuscles.  If  these  were  taken  out 
the  remaining  part  of  the  blood  would  be  colorless, 
and  would  look  like  water.  The  red  corpuscles  change 
from  a  dark  bluish-red  to  a  bright  red  color  when  they 
take  in  oxygen  in  the  lungs.  When  the  red  corpuscles 
lose  oxygen  in  the  capillaries  their  color  changes  from 
a  bright  red  to  a  dark  bluish-red.  It  is  for  this  reason 
that  the  blood  has  a  bright  red  color  in  the  arteries 
and  a  dark  bluish-red  color  in  the  veins. 

The  white  corpuscles. — The  white  corpuscles  are 
slightly  larger  than  the  red  ones,  and  are  fewer  in 
number.  A  drop  of  blood  has  about  five  hundred 
red  corpuscles  for  each  white  one. 

The  white  corpuscles  are  made  up  of  a  very  soft, 
jelly-like  substance,  and  they  can  readily  change  their 
shape.  At  one  time  a  white  corpuscle  may  be  quite 
round.  At  another  time  part  of  the  corpuscle  may 
be  pushed  out  so  as  to  resemble  a  tiny  arm,  and  a 
corpuscle  may  have  more  than  one  of  these  little  arms 


HOW    THE   BLOOD   BUILDS   UP   THE   BODY  85 

at  the  same  time.  A  small  arm  is  able  to  encircle 
little  solid  particles  that  have  found  their  way  into 
the  blood  and  are  injuring  our  health.  Such  particles 
may  thus  be  enclosed  in  the  body  of  a  white  corpuscle 
and  be  destroyed. 

In  this  way  white  corpuscles  protect  our  bodies 
from  germs  of  disease.  When  disease  germs,  or  bac- 
teria, enter  the  body  through  a  wound,  or  in  any  other 
way,  white  corpuscles  fight  them  and  try  to  destroy 
them.  Sometimes,  when  the  bacteria  are  very  strong, 
the  battle  becomes  so  fierce  that  many  white  corpus- 
cles are  killed.  The  dead  bodies  of  these  corpuscles 
then  form  what  we  call  matter,  or  pus. 

It  is  believed  also  that  the  white  corpuscles  aid,  in 
some  way,  in  the  clotting  of  blood. 

The  heart, — Many  of  you  have  seen  a  sheep's  heart. 
It  is  a  good  deal  like  a  human  heart.  The  heart  is 
made  of  muscle.  If  you  cut  a  sheep's  heart  open  you 
will  see  that  it  is  not  solid  muscle,  but  within  it  are 
hollow  places,  called  cavities.  You  will  also  see  how 
thick  and  strong  the  walls  of  these  cavities  are. 

The  human  heart  is  about  the  size  of  a  man's  fist. 
A  partition  down  the  middle  of  it  divides  it  into  a 
right  side  and  a  left  side.  This  partition  wall  is  so 
tight  and  strong  that  the  blood  in  one  side  cannot  get 


86 


PHYSIOLOGY   FOR  CHILDREN 


through  into  the  other  side.    Each  side  is  divided  into 
an  upper  cavity  and  a  lower  cavity. 

How  the  heart  works — If  you  take  in  your  hand 
a  small  rubber  ball  that  has  a  hole  in  it,  squeeze  the 


SECTION    OF   HEART,    SHOWING   THE   FOUR    CAVITIES. 

air  out  of  it,  and  then  hold  it  in  a  basin  of  water,  the 
ball  will  fill  with  water  as  soon  as  you  open  your 
hand.  If  you  now  close  your  hand  tightly  upon  the 
ball  you  will  force  the  water  out  through  the  hole.  If 
you  open  and  close  your  hand  slowly  several  times,  you 


HOW  THE  BLOOD  BUILDS  UP  THE  BODY       87 

will  see  that  each  time  you  open  your  hand  the  ball 
fills  with  water,  and  each  time  you  close  your  hand 
the  water  is  forced  out. 

The  four  cavities  of  the  heart  are  filled  and  emptied 
in  a  somewhat  similar  way.  The  muscles  of  which  the 
walls  of  the  heart  are  composed  contract  and  relax. 
When  they  relax  they  open  the  cavities,  and  blood 
runs  in  from  the  veins.  When  these  muscles  contract 
they  close  the  cavities,  and  blood  is  squeezed  out  into 
the  arteries.  Both  sides  of  the  heart,  the  right  side 
and  the  left  side,  open  at  the  same  time  and  close  at 
the  same  time. 

The  closing  of  the  right  side  forces  dark  bluish-red 
blood  into  and  through  the  lungs,  and  on  into  the  left 
side  of  the  heart.  While  going  through  the  lungs  this 
dark  blood,  just  in  a  twinkling,  receives  oxygen  from 
the  air,  and  is  changed  to  a  bright  red  color. 

The  left  side  closes  with  great  power.  Its  closing 
sends  the  bright  red  blood  rushing  out  through  the 
large  artery,  the  aorta,  on  through  the  small  arteries, 
through  the  tiny  capillaries,  through  the  little  veins, 
and  back  through  the  large  veins  into  the  right  side 
of  the  heart. 

The  heart,  then,  is  like  two  little  pumps  fastened  to- 
gether. The  right  side  forces  the  dark  blood  through 


88  PHYSIOLOGY  FOTC  CHILDEEN 

the  lungs ;  the  left  side,  which  is  stronger,  forces  the 
bright  red  blood  through  the  body. 

The  beat  of  the  heart — The  heart  lies  against 
the  chest  wall  just  behind  the  ribs.  The  small  end 
of  it  points  downwards,  and  a  little  towards  the  left 
side  of  the  body.  As  the  heart  contracts  suddenly 
and  with  great  force  it  jars  the  chest  wall.  Each  con- 
traction of  the  heart  is  called  a  beat.  When  the  heart 
is  beating  slowly  and  quietly  it  may  not  be  easy  to  feel 
the  jar.  But  active  exercise,  such  as  running,  causes 
the  heart  to  beat  faster  and  stronger,  and  then  the  jar 
is  easily  felt  each  time  the  heart  beats. 

The  pulse. — The  pulse  is  caused  by  the  beating  of 
the  heart.  It  can  be  felt  in  all  the  arteries,  but  not  in 
the  capillaries  or  veins.  A  doctor  usually  feels  your 
pulse  at  the  wrist  because  there  the  artery  is  near  the 
surface.  In  health  the  heart  beats,  on  an  average, 
about  seventy -two  times  a  minute ;  but  during  fever  it 
beats  faster,  and  so  the  doctor  counts  the  pulse  beats 
to  help  him  find  out  the  condition  of  your  heart. 

Health  of  the  heart. — What  a  wonderful  little 
worker  the  heart  is  !  Day  and  night,  summer  and 
winter,  year  after  year,  it  beats  on  and  on,  never  taking 
a  holiday.  If  yours  should  stop  beating  for  just  one 
short  minute  you  would  die. 


HOW  THE  BLOOD  BUILDS  UP  THE  BODY       89 

Without  a  sound,  strong  heart  you  can  never  be 
perfectly  healthy.  Some  diseases  that  are  often  caused 
by  dampness  and  by  wearing  wet  clothing  are  liable 
to  injure  the  heart.  For  this  reason  every  one  should 
remember  these  short  rules : 

Never  sit  on  wet  grass  or  damp  ground. 

Never  sleep  in  a  damp  bed  or  in  a  bedroom  with 
damp  walls. 

Whenever  your  clothing  gets  wet  put  on  dry 
clothing  as  soon  as  you  can. 

Do  not  live  in  a  house  with  a  damp  cellar  or  with 
damp  walls. 

Keep  your  feet  dry  and  warm. 

How  the  circulation  may  be  affected.  —  The 
circulation  of  the  blood  may  be  hindered  in  many 
ways.  Large  veins  lie  just  under  the  skin  and  near 
the  surface.  Tight  clothing  prevents  the  blood  from 
flowing  freely  and  easily  through  these  veins.  Tight 
boots  make  cold  feet  because  they  prevent  the  free 
flow  of  the  blood.  Tight  garters,  also,  are  a  frequent 
cause  of  cold  feet.  The  heart  needs  plenty  of  room  in 
order  to  work  well.  Tight  waists  and  other  tight 
clothing  press  in  the  soft  walls  of  the  chest  and  inter- 
fere with  the  heart. 

Exercise  makes  the  blood  circulate  well.     A  brisk 


90  PHYSIOLOGY   FOE   CHILDREN 

walk  brings  a  warm  glow  to  the  skin.  A  game  of 
ball  or  blind  man's  buff  will  quicken  the  circulation 
and  warm  up  the  body.  Such  exercise  will  help  to 
make  you  healthy  and  strong. 

A  daily  bath  will  aid  the  circulation,  if  it  is  fol- 
lowed by  brisk  rubbing  with  a  coarse  towel  till  a 
warm  glow  is  felt  in  the  skin. 

Effect  of  alcohol  on  the  heart. — The  first  effect  of 
alcohol  on  the  heart  is  to  make  it  beat  faster  than 
usual,  but  after  a  short  time  the  heart  will  beat  more 
slowly  than  it  did  before  the  alcohol  was  taken.  If, 
however,  a  very  large  amount  is  taken,  as  is  sometimes 
done  on  a  wager,  it  may  stop  the  beating  of  the  heart 
almost  immediately,  and  cause  death. 

Some  alcoholic  liquors,  such  as  wine  and  beer,  have 
a  tendency  to  produce  too  much  fat.  A  great  deal  of 
fat  often  forms  on  the  surface  of  the  heart  and  between 
the  fibres  of  its  muscles,  so  that  the  heart  becomes 
weaker  than  it  was.  This  diseased  condition  is  called 
fatty  heart. 

Effect  of  alcohol  on  the  circulation. — The  walls 
of  the  arteries  contain  involuntary  muscles.  When 
these  muscles  contract  the  arteries  become  smaller 
and  will  hold  less  blood  ;  when  these  muscles  relax  the 
arteries  become  larger  and  will  hold  mo-re  bloodc 


HOW   THE   BLOOD   BUILDS   UP   THE  BODY 


91 


Nerves  ending  in  these  muscles  cause  them  co  contract 
and  relax. 

Alcohol  weakens  the  nerves  which  control  the  mus- 
cles of  the  arteries,  and  then  the  muscles  relax.     Thus 


APPEARANCE  OF  ARTERIES  IN 
LINING  OF  HEALTHY  STOMACH. 


APPEARANCE  OF  ARTERIES  EN- 
LARGED BY  ALCOHOL. 


alcohol  causes  the  small  arteries  throughout  the  body 
to  become  enlarged  and  to  hold  more  blood  than  usual. 
A  well-known  illustration  of  this  is  the  flush  of  the 
face  that  follows  the  drinking  of  alcoholic  liquor. 

The  continued  use  of  alcoholic  liquor,  especially  of 
beer,  tends  to  the  forming  of  fat  in  the  walls  of  the 
arteries.  This  fat  weakens  the  arteries  and  makes  them 
less  able  to  bear  the  pressure  of  the  blood  as  it  is 
forced  through  them  by  the  heart.  Any  sudden  strain 


92  PHYSIOLOGY  FOR  CHILDREN 

on  the  wall  of  an  artery  may  then  cause  a  break,  which 
may  produce  death. 

Effect    of  alcohol    on  the    blood.— Besides    its 

effect  on  the  heart  and  on  the  arteries,  alcohol  affects 
also  the  blood  itself.  It  acts  upon  the  red  corpuscles 
of  the  blood  and  lessens  their  power  to  take  up  oxygen 
and  give  it  out  to  the  tissues.  In  this  way  every  organ 
of  the  body  is  affected  by  alcohol  in  the  blood,  for 
every  part  of  the  body  needs  oxygen  and  depends 
chiefly  upon  the  blood  for  its  supply. 

Effect  of  tobacco  on  the  heart. — The  use  of 
tobacco  often  causes  the  heart'  to  beat  irregularly, 
because  tobacco  contains  a  deadly  poison  called  nico- 
tine, which  acts  upon  the  nerves  that  control  the  beat- 
ing of  the  heart.  Physicians  use  the  name  "  tobacco 
heart  "  in  speaking  of  a  heart  which  has  been  injured 
by  nicotine.  In  the  mildest  form  of  this  disease  there 
is  a  slight  fluttering  of  the  heart  and  an  uncomfortable 
feeling  in  the  left  side  of  the  chest.  In  more  severe 
attacks  the  heart  beats  violently  and  causes  great 
distress. 

We  have  learned  that : 

1.  Every  part  of  the  body  is  supplied  with  blood  tubes. 

2.  The  heart  forces  blood  through  these  tubes. 

3.  The  blood  carries  food  and  oxygen  to  all  parts  of  the  body,  and 
brings  back  waste  matter  from  all  parts. 


HOW   THE  BLOOD   BUILDS    UP  THE  BODY  93 

4.  The  tubes  through  which  blood  goes  out  to  all  parts  from  the  heart 
arc  called  arteries. 

5.  The  arteries  divide  up  and  become  smaller  and  smaller,  until  they 
can  be  seen  only  with  a  microscope,  and  are  then  called  capillaries. 

6.  As  the  blood  is  going  through  the  capillaries,  food  and  oxygen  in  the 
blood  go  through  the  walls  of  the   capillaries  to  the  tissues  ;  and  waste 
matter  in  the  tissues  comes  through  these  walls  to  the  blood. 

7.  The  capillaries  unite  and  form  larger  tubes,  called  veins,  which  carry 
the  blood  back  to  the  heart. 

8.  Blood  can  form  a  clot  and  thus  stop  bleeding  from  a  small  wound. 

9.  Blood  consists  of  a  watery  fluid  and  corpuscles  floating  in  it. 

10.  The  red  corpuscles  give  the  blood  its  color. 

11.  After  these  corpuscles  take  in  oxygen  from  the  air  in  the  lungs  they 
have  a  bright  red  color. 

12.  After  they  give  up  oxygen  to  the  tissues  they  have  a  dark  bluish-red 
color. 

13.  The  white  corpuscles  help  to  protect  our  body  from  disease. 

14.  The  heart  is  made  up  of  muscle.      It  contains  four  cavities,  which 
close  when  it  contracts  and  open  when  it  relaxes. 

15.  Blood  flows  from  veins  into  these  cavities  when  they  are  open,  prd  is 
forced  out  into  the  arteries  when  the  cavities  close. 

16.  Each  time  the  heart  contracts  it  is  said  to  beat. 

17.  With  each  beat  there  is  a  throb  of  the  arteries  which  is  called  a  pulse. 

18.  The  use  of  alcohol  may  injure  the  heart,  the  arteries,  and  the  blood. 

19.  The  use  of  tobacco  may  injure  the  heart. 


CHAPTER  VIII 


DRINKS    WHICH    CONTAIN   ALCOHOL 


Fermentation.  —  While 
apples  are  ripening,  sugar  is 
formed  in  them.  The  juice  of 
apples  is  composed  largely  of 
water,  in  which  the  sugar  is 
dissolved.  When  the  juice  is 
first  pressed  out  of  the  apples 
it  contains  no  alcohol.  But 
unless  it  is  kept  cold  the  sugar 
in  the  juice  quickly  changes 
FERMENTATION  IN  A  GLASS  into  alcohol  and  a  gas,  which 

our  fathers  called  carbonic  acid 

gas,  but  which  to-day  is  called  carbon  dioxide.  This 
gas  escapes  in  little  bubbles,  which  may  be  seen  rising 
up  through  the  liquid,  but  the  alcohol  remains  in  it. 

The  process  by  which  sugar  is  changed  into  alcohol 
and  carbon  dioxide  is  called  fermentation.  The  sugar 
may  be  obtained  from  the  juice  of  ripe  fruits,  and 
from  the  sap  of  such  plants  as  the  sugar-cane,  from 
the  starch  of  potatoes  or  of  such  grains  as  wheat, 
corn,  rye,  and  barley. 

Fermentation  is  caused  by  little  plants,  called  fer- 


DRINKS    WHICH   CONTAIN  ALCOHOL  95 

ments.  They  are  so  small  that  they  cannot  be  seen 
without  the  aid  of  a  microscope.  These  ferments 
float  about  in  the  air  and  lodge  on  the  skin  and  stems 
of  apples,  grapes,  and  other  fruit. 

When  the  grapes  and  apples  are  crushed  and 
pressed,  ferments  are  washed  from  them  with  the 
juice,  or  fall  into  it  from  the  air.  Having  once 
entered  the  juice,  they  grow  quickly  and  increase  in 
number  rapidly.  While  growing  they  act  on  the 
sugar  and  change  it  into  alcohol  and  carbon  dioxide. 

How  malt  liquors  are  made.  —  Beer,  ale,  and 
porter  are  made  from  grain.  The  grain  is  moistened 
and  then  allowed  to  sprout.  By  this  means  the  starch 
of  the  grain  is  changed  into  sugar.  The  grain,  or 
malt  as  it  is  now  called,  is  then  dried  and  ground,  and 
the  sugar  is  dissolved  out  with  water.  This  is  then 
boiled  with  hops,  and  yeast  is  added  because  it  con- 
tains a  ferment.  It  sets  up  fermentation,  by  which 
the  sugar  is  changed  into  alcohol  and  carbon  dioxide. 

How  distilled  liquors  are  made.— When  water 
is  boiled  it  passes  away  as  a  vapor,  called  steam. 
When  alcohol  is  boiled  it  also  passes  away  as  vapor. 
As  the  steam,  or  vapor,  of  a  liquid  rises  it  may  be 
collected.  If  it  is  allowed  to  cool  it  quickly  changes 
back  to  a  liquid. 


96  PHYSIOLOGY   FOK  CHILDREN 

When  wine  is  heated  the  alcohol  in  it  boils  and 
turns  to  vapor,  and  part  of  the  water  changes  to 
steam  at  the  same  time.  The  two  vapors  are  then 
collected  and  allowed  to  cool.  The  entire  process  is 
called  distillation.  The  liquid  into  which  the  vapors 
cool  is  called  brandy.  A  pint  of  brandy  contains 
more  alcohol  and  less  water  than  a  pint  of  wine. 

Whisky  is  made  from  grain.  After  the  grain  has 
sprouted,  and  its  starch  has  changed  to  sugar,  water 
is  added  and  alcohol  is  formed  by  fermentation,  just 
as  in  the  making  of  beer.  Then  it  goes  through  the 
process  of  distillation.  The  alcohol  and  water  that 
pass  off  as  vapor  are  collected  and  cooled  into  the 
liquid  called  whisky,  which,  like  brandy,  is  made  up 
mainly  of  alcohol  and  water  in  about  equal  parts. 

Rum  is  made  from  the  sap  of  the  sugar-cane.  The 
sap  is  first  fermented  and  then  distilled. 

What  alcohol  is  like. — Alcohol  is  a  colorless, 
transparent  liquid.  It  looks  like  water,  but  it  has  a 
sharp,  burning  taste.  It  acts  very  differently  from 
water  on  the  organs  and  tissues  of  the  body.  Water 
is  necessary  for  life.  We  should  die  if  we  could  not 
get  it.  Alcohol  is  not  only  not  necessary,  but  as  a 
beverage  it  is  injurious  to'  health,  and  thousands  die 
every  year  from  drinking  liquors  which  contain  it. 


DRINKS   WHICH   CONTAIN  ALCOHOL  97 

Is  alcoholic  liquor  a  food? — We  have  learned 
that  one  use  of  food  is  to  repair  waste  and  build  up 
the  body.  It  is  from  food  that  blood,  bone,  muscle, 
nerve,  and  other  parts  of  the  body  are  made.  Alcohol 
contains  none  of  the  material  necessary  to  repair  waste 
or  build  up  the  body. 

Another  use  of  food  is  to  produce  heat  and  power 
to  work.  The  food  that  contains  the  material  neces- 
sary for  this  is  carried  by  the  blood  to  the  tissues, 
and  oxygen  from  the  air  we  breathe  is  carried  by  the 
blood  to  the  tissues  at  the  same  time.  This  food  and 
oxygen  unite  in  the  tissues,  and  produce  heat  and 
power  to  work. 

Experiments  show  that  some  of  the  alcohol  which  is 
taken  into  the  body  unites  with  oxygen  in  the  tissues. 
When  alcohol  unites  with  oxygen  in  the  tissues  some 
heat  is  produced.  But  the  alcohol  at  the  same  time 
causes  the  blood  tubes  of  the  skin  to  become  larger,  so 
that  more  blood  than  usual  flows  to  the  surface  of 
the  body,  and  loses  heat  by  coming  near  the  air. 
More  heat  is  thus  lost  from  the  surface  of  the  body 
than  is  produced  in  the  tissues.  Therefore  the  effect 
of  alcohol  is  to  lower  the  temperature  of  the  body. 

When  alcohol  unites  with  oxygen  in  the  tissues, 
some  power  to  work  is  produced.  But  the  general 


98 


PHYSIOLOGY   FOE   CHILDREN 


strength  of  the  body 
is  not  increased,  be- 
cause the  alcohol  at 
at  the  same  time 
injures  the  tissues. 
It  lessens  the  power 
of  the  blood  to  carry 
oxygen,  and  acts 
upon  the  nerves  to 
lessen,  or  destroy, 
their  control  over 
the  muscles.  The 
amount  of  injury 
done  in  this  way 
depends  upon  the 
quantity  of  alcohol 
taken.  The  effect  of  alcohol  in  lessening  the  muscular 
strength  of  the  body  is  recognized,  as  we  have  learned, 
by  athletes,  for  when  they  are  training  for  contests 
they  do  not  use  it. 

Experiments  by  means  of  a  weight  attached  to  one 
of  the  fingers  (see  page  40)  also  show  that  the  mus- 
cles are  affected  by  small  quantities  of  alcohol,  for  it 
was  found  that  the  muscles  of  the  finger  could  do 
more  work  when  no  alcohol  was  taken  than  they 


ATHLETIC   STRENGTH. 


DRINKS   WHICH   CONTAIN  ALCOHOL  99 

could  when  even  a  small  amount  was  taken.  Alcohol, 
therefore,  does  not  produce  power  to  work,  for  it 
weakens  instead  of  strengthening  the  muscles.  It 
does  not  aid  in  keeping  the  body  warm,  for  it  in- 
creases the  loss  of  heat  from  the  body.  And  it  cannot 
repair  waste  or  build  up  the  body,  for  it  contains  none 
of  the  material  by  which  this  is  done.  Alcohol,  then, 
is  not  a  food,  in  the  ordinary  sense  in  which  we  use 
that  term. 

Poisonous  action  of  alcoholic  liquor. — In  some 
cases  where  only  a  small  amount  of  alcoholic  liquor  is 
taken,  the  injury  to  the  tissues  is  so  slight,  and  its 
effects  pass  off  so  quickly  that  the  harm  done  is  not 
noticed  by  the  one  who  takes  it.  Yet  the  taking  of 
alcohol  even  in  small  amounts  is  dangerous,  for  small 
amounts  often  create  an  uncontrollable  appetite  for 
larger  amounts ;  and  when  these  are  taken  the  tissues 
are  so  seriously  injured  that  the  harmful  effects  do 
not  escape  notice.  It  is  well  known  that  alcoholic 
liquor  in  large  amounts  produces  a  condition  of  intox- 
ication. The  drowsiness,  stupor,  and  loss  of  conscious- 
ness in  intoxication  are  caused  by  the  action  of  alcohol 
on  the  brain.  This  action  is  entirely  different  from 
that  produced  by  food  of  any  kind,  but  is  quite  like 
the  action  produced  on  the  brain  by  a  class  of  sub- 


100  PHYSIOLOGY   FOR  CHILDREN 

stances  called  narcotic  poisons.     In  many  cases  death 
has  followed  the  drinking  of  alcoholic  liquor. 

The  papers  frequently  report  cases  similar  to  the 
following,  and  a  record  of  them  can  easily  be  found  in 
the  office  of  the  Board  of  Health  in  the  city  where 
they  occur: 

te  Sarah  Hochman,  the  three-year-old  daughter  of  Harris 
Hochman,  living  at  385  Marion  Street,  Brooklyn,  died  last 
night  in  St.  Mary's  Hospital.  The  child  was  admitted  to  the 
hospital  early  in  the  morning,  suffering  from  alcoholic  poison- 
ing. She  was  in  a  stupor  at  the  time,  in  which  condition  she 
remained  up  to  the  time  of  her  death.  The  poisoning  was  the 
result  of  the  child's  eating  blackberries  prepared  in  alcohol." — 
New  York  Herald,  August  3,  1902. 

"  Seven-year-old  Pietro  Gordano  died  early  yesterday  morn- 
ing in  Eoosevelt  Hospital  of  acute  alcoholism.  On  Sunday 
evening  there  was  a  wedding  at  his  home,  209  West  Sixty- 
fourth  Street.  Pietro  got  a  seat  at  the  wedding  table,  and  in 
some  way  managed  to  get  hold  of  a  quart  bottle  of  Italian 
wine,  a  little  more  than  half  full,  and  to  drink  most  of  it." — 
New  York  Sun,  January  8,  1902. 

In  such  cases  the  poisonous  action  of  the  alcohol 
is  plainly  shown.  In  fact,  alcoholic  poisoning  is  a 
medical  term  used  in  stating  the  cause  of  death. 

Mistaken  notions  about  alcoholic  drinks.— One 


DRINKS   WHICH   CONTAIN  A^CG^QL   ^W^Ol 

reason  why  alcoholic "  drinks  are  used  is  that  people 
have  mistaken  notions  about  their  value.  The  rosy 
look  and  the  fleshy  appearance  which  they  often  pro- 
duce cause  some  people  to  thijik  that  alcohol  is  good 
for  the  health.  But  this  is  not  true.  For  those  who 
are  in  the  habit  of  taking  alcoholic  drinks,  even  in 
moderate  quantities,  are  more  likely  to  become  ill,  and 
are  less  likely  to  recover  from  illness  than  those  who 
do  not  drink  alcohol  at  all. 

Another   mistaken   notion   in   regard    to   alcoholic 

O 

drinks  is  that  they  must  be  good  because  they  are 
made  from  grain  and  fruit.  People  who  are  influ- 
enced by  this  notion  forget  that  grain  and  fruit  are 
not  always  good  for  food.  The  grain  may  become 
musty  and  the  fruit  may  decay,  the  change  which  has 
taken  place  making  them  entirely  unfit  for  food.  The 
fact  that  ripe  grain  and  fruit  are  good  for  food  does 
not  prove  that  alcohol  made  from  them  is  good  for 
food.  Grain  and  fruit  in  their  natural  state  do  not 
contain  any  alcohol.  They  must  first  be  changed  by 
fermentation  before  alcohol  can  be  obtained  from 
them. 

Mistaken  notions  in  regard  to  the  power  of  alcohol 
to  produce  muscular  strength  also  influence  some  per- 
sons to  use  it.  It  has,  however,  been  proved  that  men 


PHYSIOLOGY   FOB  CHILDREN 


MUSCULAR  STRENGTH. 


can  do  more  work  without  alcoholic  liquor  than  they 
can  when  they  use  it. 

Benjamin  Franklin,  who  was  one  of  the  greatest 
Americans  of  Washington's  time,  was  a  printer  when 
he  was  a  young  man.  In  his  autobiography  he  gives 
an  account  of  his  experience  as  a  printer  in  London. 
He  says,  UI  drank  only  water;  the  other  workmen, 
nearly  fifty  in  number,  were  great  drinkers  of  beer. 
On  occasion  I  carried  up  and  down  stairs  a  large  form 
of  types  in  each  hand,  when  others  carried  but  one 
in  both  hands.  They  wondered  to  see,  from  this  and 
several  instances,  that  the  Water- American,  as  they 


DRINKS   WHICH   CONTAIN   ALCOHOL  103 

called  me,  was  stronger  than  themselves,  who  drank 
strong  beer.  My  companion  at  the  press  drank  every 
day  a  pint  before  breakfast,  a  pint  at  breakfast  with 
his  bread  and  cheese,  a  pint  between  breakfast  and 
dinner,  a  pint  at  dinner,  a  pint  in  the  afternoon  about 
six  o'clock,  and  another  when  he  had  done  his  day's 
work.  I  thought  it  a  detestable  custom,  but  it  was 
necessary,  he  supposed,  to  drink  strong  beer  that  he 
might  be  strong  to  labor." 

The  idea  that  the  temperate  use  of  alcoholic  liquor 
prolongs  life  is  another  mistaken  notion,  as  is  proved 
by  the  experience  of  life  insurance  companies.  The 
following  is  from  a  letter  received  from  Dr.  Henry 
Tuck,  Vice-President  of  the  New  York  Life  Insurance 
Company. 

NEW  YORK,  February  24,  1900. 

Dear  Sir :  Your  letter  of  February  22d,  asking  my  opinion, 
based  upon  my  experience  in  life  insurance,  as  to  the  effect  of 
alcohol  upon  the  human  system,  is  duly  received. 

My  personal  opinion  is  that  every  well  man,  woman,  or  child 
is  better  without  alcohol  in  any  form. 

To  answer  the  one  question  that  you  ask,  as  to  the  effect  of 
alcohol  upon  the  length  of  life,  it  is  proved  beyond  question 
that  the  habitual,  though  temperate  use  of  alcohol  is  unfavor- 
able to  long  life.  This  question  has  been  carefully  gone  into 
several  times  within  the  past  few  years  by  some  of  the  insur- 


104  PHYSIOLOGY   FOK   CHILDREN 

ance  and  medical  journals,  to  which,  if  you  care  to  go  fully  into 
the  question,  I  would  refer  you  for  further  information, 

Yours  very  truly, 

HENRY  TUCK, 

Vice- President. 

There  are  in  England  and  Scotland  life  insurance 
companies  which  separate  their  business  into  two 
sections.  In  one  section  they  insure  the  lives  of 
abstainers,  those  who  do  not  drink  alcoholic  liquors 
at  all.  In  the  other  section  they  insure  the  lives  of 
people  who  are  moderate  drinkers.  The  records  of 
these  companies  show  that  the  use  of  alcohol,  even  in 
moderate  amounts,  shortens  life. 

The  appetite  for  alcohol. — It  is  because  the  appe- 
tite for  alcohol  grows  on  one  that  many  who  begin  as 
moderate  drinkers,  and  intend  to  remain  so,  become 
hopeless  drunkards.  This  is  the  greatest  danger  of 
moderate  drinking.  With  many  people,  the  small 
quantity  of  alcohol  taken  at  first  causes  a  desire  for 
more  and,  as  the  appetite  increases,  larger  quantities 
are  taken,  until  the  craving  for  alcohol  becomes  so 
strong  that  it  cannot  be  resisted. 

Any  alcoholic  drink  may  cause  this  unnatural  and 
uncontrollable  appetite  for  alcohol. 


DRINKS    WHICH    CONTAIN   ALCOHOL  105 

All  people  agree  that  the  use  of  alcoholic  liquor  in 
large  amounts  results  in  great  injury  and  misery.  In 
every  neighborhood  there  are  men  who  were  once  kind- 
hearted,  noble,  and  prosperous,  but  who  have  become 
wrecks  through  drink,  and  are  so  completely  controlled 
by  their  appetite  for  it  that  they  will  secure  it  even 
at  the  cost  of  necessary  food  and  clothing  for  them- 
selves and  families.  Many,  and  perhaps  all  of  these 
people,  believed  when  they  began  drinking  that  they 
could  control  themselves  and  stop  whenever  they 
wished;  but  no  one  can  tell  in  advance  that  the  appe- 
tite for  alcohol  will  not,  in  time,  gain  complete  control 
over  him.  Since  this  is  true,  it  is  safe  to  say  that  the 
right  course  is  not  to  begin  to  drink  alcoholic  liquors. 


We  have  learned  that : 

1.  Alcohol  is  made  from  sugar  by  fermentation. 

2.  Alcohol  is  not  a  food. 

3.  When  alcohol  produces  intoxication,  it  acts  as  a  narcotic  poison. 

4.  The  reports  of  life  insurance  companies  show  that  people  who  do 
not  drink    alcoholic  liquor  live  longer,   on  the  average,  than  people  who 
do  drink  it. 

5.  Some  people  drink  alcoholic  liquor  because  they  have  false  opinions 
about  it. 

6.  A  great  danger  in  the  moderate  drinking  of  alcoholic  liquor  is  the 
forming  of  a  habit  of  drinking  that  cannot  be  given  up. 

7.  No  one  can  tell  beforehand  whether  he  will  become  a  slave  to  liquor, 
and  therefore  it  is  better  not  to  begin  to  drink  it. 


CHAPTER   IX 

BREATHING 

The  need  of  oxygen.— If  you  mix  a  handful  of 
grain  and  a  handful  of  chaff  together  and  put  them 
in  a  dish  before  a  chicken,  the  chicken  will  pick  out 
the  grain,  which  it  does  need,  and  leave  the  chaff, 
which  it  does  not  need. 

In  somewhat  the  same  way  different  organs  of  the 
body  take  what  they  need  out  of  material  which  is 
brought  to  them,  and  do  not  take  what  they  do  not 
need.  For  example,  air  consists  of  gases  mixed  to- 
gether. One  of  these  gases  is  oxygen.  As  we  breathe, 
air  comes  in  through  the  nose  or  mouth  and  goes  down 
the  windpipe  into  the  lungs.  While  the  air  is  in  the 
lungs  they  take  from  it  oxygen,  which  we  need,  but, 
under  ordinary  conditions,  leave  the  gases  which  we 
do  not  need. 

If  you  had  a  glass  jar  full  of  oxygen  you  could  not 
see  the  oxygen,  yet  it  could  be  weighed,  and  if  a  rubber 
bag  were  filled  with  oxygen  and  you  were  to  stand  upon 
it,  the  oxygen  would  hold  you  up,  just  as  water  would 
if  the  bag  were  filled  with  water.  We  cannot  live  with- 
out oxygen  any  more  than  we  can  live  without  food. 


BREATHING  107 

How  we  breathe. — The  act  of  breathing  consists 
of  two  parts.  We  breathe  in  and  we  breathe  out. 
When  we  breathe  in  we  are  said  to  inspire,  or  inhale ; 
when  we  breathe  out,  we  are  said  to  expire,  or  exhale. 


THE    LUNGS    OF    A   NEWT. 


Breathing  in  is  called  inspiration,  and  breathing  out 
is  called  expiration. 

If  you  press  your  hands  firmly  against  the  sides  of 
your  chest,  and  breathe  a  few  times,  as  deeply  as  you 
can,  you  will  see  and  feel  your  hands  moving  as  your 
chest  becomes  larger,  and  then  smaller.  The  changes 
in  the  size  of  the  chest  are  caused  by  muscles.  One 


108  PHYSIOLOGY   FOE   CHILDREN 

of  these  muscles  is  the  partition  between  the  chest  and 
the  abdomen  ;  the  others  are  in  the  chest  wall.  When 
these  muscles  contract,  the  chest  becomes  larger ;  when 
they  relax,  it  becomes  smaller.  When  the  chest  be- 
comes larger,  it  gives  the  lungs  more  room.  The 
lungs  swell  out  at  once  and  air  comes  in  to  fill  them. 
When  the  chest  becomes  smaller,  it  presses  upon 
the  soft,  elastic  lungs,  and  forces  some  of  the  air 
out. 

A  simple  lung.— The  lungs  of  animals  are  not 
all  alike.  A  small  animal,  called  the  newt,  has  two 
very  simple  lungs.  Each  lung  consists  of  a  single 
air  sac  which  swells  out  when  air  goes  into  it,  and 
becomes  much  smaller  when  air  goes  out  of  it. 
However,  the  little  sacs  always  contain  some  air. 
They  are  never  quite  empty. 

On  page  107  we  have  a  picture  of  the  windpipe  and 
lungs  of  a  newt  when  the  lungs  are  full  of  air. 

A  great  number  of  small,  fine,  hair-like  blood  tubes 
are  fitted  nicely  into  the  walls  of  the  air  sacs.  These 
blood  tubes  are  the  lung  capillaries.  You  can  see 
them  sketched  in  the  picture.  There  are  two  things 
for  you  to  see  in  this  picture, — the  air  sacs  and  the 
lung  capillaries.  The  capillaries  hold  blood,  the  sacs 
hold  air. 


BKEATHING  109 

What  our  lungs  are  like. — We  have  two  lungs ; 
one  on  the  right  side  and  one  on  the  left  side  of  the 
chest.  The  windpipe  divides  at  its  lower  end  into 
two  tubes,  called  the  right  and  the  left  bronchus- 
one  for  each  lung.  Each  bronchus  sends  out  several 
branches,  called  bronchial  tubes,  which  branch  out 
like  the  limbs  of  a  tree  and  end  in  little  air  sacs. 
There  are  thousands  of  small  air  sacs  in  each  lung, 
and  each  of  these  air  sacs  has  a  network  of  tiny  capil- 
laries lying  in  its  wall.  As  in  a  newt's  lung,  the  capil- 
laries hold  blood,  and  the  air  sacs  hold  air. 

Changes  in  the  blood  in  the  lungs. — The  dark 
blood  flowing  along  in  the  capillaries  of  the  lungs  has 
carbon  dioxide  in  it  that  it  must  get  rid  of.  The  air 
in  the  sac  has  oxygen  in  it  which  it  can  give  up.  So, 
when  the  air  and  the  blood  come  close  to  each  other 
in  the  lungs,  two  things  happen  to  the  blood.  Carbon 
dioxide  goes  out  of  it,  and  oxygen  comes  into  it  and 
turns  it  to  a  bright  red  color.  Like  ships  at  a  dock, 
the  little  red  corpuscles  load  up  with  oxygen  in  the 
lungs.  Then  they  sail  away  in  the  blood  stream  to 
the  left  side  of  the  heart. 

Changes  in  the  air  in  the  lungs. — Changes  also 
take  place  in  the  air  in  the  lungs.  Oxygen  goes  from 
it  into  the  blood  of  the  capillaries,  while  carbon 


110  PHYSIOLOGY  FOR   CHILDREN 

dioxide  comes  from  the  blood  into  the  air.  Ths  air 
we  breathe  out  has  less  oxygen  and  more  carbon 
dioxide  in  it  than  the  air  we  breathe  in. 


LUNGS    AND    HEART.       PART   OF    LUNG    CUT    AWA?    FROM    LEFT    SIDE    TO 
SHOW   BLOOD   TUBES    AND   AIR   TUBES. 

How  good  air  is  made  bad. — Now,  the  air  which 
we  breathe  out  has  lost  some  of  its  life-giving  oxygen, 
but  contains  more  of  the  poisonous  carbon  dioxide, 
which  has  been  brought  to  it  from  all  parts  of  the 


BREATHING  111 

body  by  the  blood  in  the  veins.  If  we  breathe  in  this 
same  air  again  and  again,  it  loses  still  more  of  its 
oxygen  and  takes  up  still  more  carbon  dioxide.  Each 
person  breathes  about  eighteen  times  a  minute,  every 
breath  taking  oxygen  from  the  air  and  adding  carbon 
dioxide  to  it.  So  you  see  that  the  oxygen  in  a  room 
full  of  people  would  soon  be  used  up,  and  the  air 
would  contain  a  dangerous  amount  of  carbon  dioxide 
unless  fresh  air  were  let  in. 

A  lamp  or  gas  jet  burning  in  a  room  takes  away 
oxygen  from  the  air  and  adds  carbon  dioxide  to  it, 
just  as  you  do  by  breathing. 

A  damp,  mouldy  cellar  may  spoil  the  air  in  a  house. 
The  air  cannot  be  wholesome  when  decaying  fruit  or 
vegetables  are  left  in  the  cellar.  Pipes  connected  with 
closets,  sinks,  "baths,  or  wash-basins  may  allow  gas  to 
escape  and  make  the  air  of  a  house  poisonous. 

Coal  stoves  give  off  much  poisonous  gas  which 
should  go  up  the  chimney,  but  if  the  damper  leading 
to  the  chimney  is  closed  and  the  stove  is  left  open, 
much  of  this  gas  finds  its  way  through  the  house. 
Enough  of  it  may  escape  in  a  few  hours  to  cause  the 
death  of  those  who  are  in  the  house. 

The  injurious  effects  of  breathing  bad  air. — 
You  cannot  have  good  health  if  you-  breathe  bad  air 


112  PHYSIOLOGY   FOE   CHILDEEN 

day  after  day.  Bad  air  affects  the  brain  and  causes 
headache  and  other  uncomfortable  feelings. 

It  affects  the  blood  most  of  all.  Those  who  spend 
much  time  in  badly  ventilated  rooms  are  always  pale. 
They  have  a  sickly  appearance  because  the  little  red 
corpuscles  do  not  get  enough  oxygen.  The  muscles 
become  weak  owing  to  the  poor  quality  of  the  blood. 

Bad  air,  by  weakening  the  body,  makes  you  more 
likely  to  take  any  disease  to  which  you  may  be  ex- 
posed. The  air  from  damp  cellars  and  damp  houses  is 
a  cause  of  bronchitis,  rheumatism,  and  heart  disease. 

Ventilation. — The  rooms  of  a  house  are  usually 
well  ventilated  in  summer  because  the  doors  and  win- 
dows are  kept  open.  The  cellars,  however,  are  often 
neglected,  even  in  warm  weather.  Every  cellar  should 
have  at  least  two  windows,  which  should  be  placed  so 
as  to  allow  a  current  of  air  to  blow  through  the  cellar. 

Houses  are  often  badly  ventilated  in  winter,  for  then 
the  doors  and  windows  are  closed  to  keep  out  the  cold 
air.  It  is  true  that  even  then  some  of  the  foul  air  of  a 
house  finds  its  way  out,  and  some  pure,  fresh  air  finds 
its  way  in.  This  happens  each  time  a  door  is  opened. 
Unless  the  windows  and  doors  are  very  tight,  foul  air 
will  find  its  way  out  through  cracks  also,  and  fresh  air 
will  come  in  by  the  same  way.  In  rooms  in  which  a 


BREATHING  113 

fire  is  burning  there  will  be  another  outward  current 
of  air  through  the  chimney,  while  air  will  come  in 
through  the  small  openings  around  the  windows  and 
doors.  Still,  these  means  are  not  sufficient  to  furnish 
fresh  air  for  the  rooms  of  a  house  when  the  doors  and 
windows  are  closed. 

In  every  house  there  should  be  some  special  way 
provided  so  that  a  sufficient  supply  of  fresh  air  may 
come  into  each  room  and  the  foul  air  may  go  out. 

Thorough  ventilation  of  the  house  is  desirable,  but 
that  alone  will  not  keep  us  in  health.  Every  one 
should  spend  a  part  of  each  day  out  of  doors.  Fresh 
air  and  sunshine  are  better  than  medicine.  On  cold 
days  put  on  extra  clothing,  but  do  not  let  cold  weather 
keep  you  from  going  out.  Those  who  go  out  every 
day  are  far  less  likely  to  take  cold  than  those  who  are 
too  much  in  the  house. 

Effect  of  alcohol  on  the  lungs. — Alcohol 
weakens  the  tissues  of  the  lungs  and  lessens  their 
power  to  resist  disease.  Those  who  drink  alcoholic 
liquor  are  more  likely  to  have  consumption  of  the 
lungs  than  those  who  do  not  drink  it.  It  is  well 
known,  too,  that  those  who  are  in  the  habit  of  drink- 
ing alcoholic  liquor  are  less  likely  to  recover  from 
pneumonia  than  those  who  do  not  use  it. 


114  PHYSIOLOGY   FOE   CHILDREN 

Effect   of  tobacco  on  the  throat  and  lungs. — 

Smokers  often  suffer  from  a  constant  irritation  of  the 
throat  and  bronchial  tubes,  and  even  inflammation  of 
the  throat  is  common  among  them. 

The  practice  of  taking  smoke  into  the  lungs  is  always 
harmful.  It  irritates  the  lungs  and  allows  a  larger 
amount  of  poison  from  the  smoke  to  be  taken  into  the 
body. 

We  have  learned  that : 

1.  We  breathe  air  in  order  to  get  oxygen  from  it. 

2.  In  inspiration  the  chest  increases  in  size,  and  in  expiration  it  becomes 
smaller. 

3.  When  the  chest  becomes  larger  the  lungs  swell  out  and  air  comes  in 
to  fill  them. 

4.  When  the  chest  becomes  smaller  it  presses  upon  the  lungs  and  forces 
air  out  of  them. 

5.  The  newt  has  very  simple  lungs. 

6.  Very  fine  blood  tubes  are  in  the  walls  of  the  newt's  lungs. 

7.  Our  lungs  contain  thousands  of  air  sacs,  each  one  of  which  is  like  a 
newt's  air  sac. 

8.  The  air  sac  contains  air,  and  the  capillaries  in  its  wall  contain  blood. 

9.  Oxygen  passes  from  the  air  in  the  air  sac  to  the  blood  in  the  capil- 
laries, and  carbon  dioxide  passes  from  the  blood  to  the  air. 

10.  Red  corpuscles  in  the  blood  load  up  with  oxygen  in  the  lungs  and 
carry  it  to  all  parts  of  the  body. 

11.  Breathing  bad  air  is  injurious. 

12.  Houses  should  be  well  ventilated. 

13.  Alcohol  injures  the  tissues  of  the  lungs. 

14.  The  throat  and  lungs  may  be  injured  by  smoking  tobacco. 


CHAPTER  X 


THE    SKIN 

What  the  skin  is  like. — Our  bodies  have  a  soft 
covering  of  skin,  which  has  two  parts,  an  outer  and  an 
inner  part.  The  outer  part  is  called  the  scarf-skin  and 
the  inner  part  the  true  skin. 

The  scarf-skin.— The  scarf-skin  consists  of  cells 
arranged  in  several  layers  one  upon  another.  Of 
course  each  layer  must  be  very  thin,  because  the 
whole  scarf-skin  is  only 
about  as  thick  as  a  thin 
sheet  of  paper.  The  outer 
layers  are  all  the  time 
wearing  out  and  being 
rubbed  off  and,  while  this 
is  going  on,  new  cells  are 
being  formed  in  the  lowest 
layer.  These  new  cells 
keep  pushing  the  cells 
above  them  out  to  the  sur- 
face, to  take  the  place  of 
those  that  are  worn  away, 
built  up  from  below  while  it  is  wearing  away  above. 


,  TRUE    SKIN.       6,  LAYERS    OF 

SCARF-SKIN. 

(Magnified.) 

Thus  the  scarf-skin  is 


116  PHYSIOLOGY   FOE  CHILDREN 

If  you  will  rub  your  arm  briskly  while  standing  in 
the  bright  sunshiny  you  will  see  many  dust-like  sj.  ecks 
floating  in  the  airc  These  are  worn-out  cells  from  the 
outer  layer  of  the  scarf-skin. 

The  cells  of  the  outer  layers  of  the  scarf-skin  have 
no  feeling,  for  they  contain  no  nerves.  If  you  prick 
the  scarf-skin  with  the  point  of  a  needle  you  will  feel 
no  pain.  Moreover,  you  will  see  no  blood,  unless 
the  point  of  the  needle  passes  on  into  the  true  skin,  for 
the  scarf-skin  contains  no  blood  tubes. 

The  coloring  matter  which  gives  us  our  complexions 
lies  in  the  deepest  layer  of  the  scarf-skin. 

If  the  scarf-skin  is  rubbed  or  pressed  day  after  day 
it  will  become  thicker.  For  this  reason  the  skin  on 
the  palm  of  the  hand  and  the  sole  of  the  foot  often 
becomes  quite  thick  and  hard.  This  explains  why 
boys  who  go  barefoot  in  the  summer  can  walk  over 
rough;  and  even  stony  ground  without  hurting  their 
feet. 

The  true  skin. — The  true  skin  lies  under  the 
scarf-skin.  It  is  full  of  blood  tubes  and  nerves. 
On  page  118  there  is  a  picture  of  a  piece  of  true 
skin.  Its  surface  is  not  smooth,  but  is  raised  at  in- 
tervals into  little  points. 

Most  of  these  points  contair    a  looped  capillary; 


THE   SKIN  117 

some  of  them  contain  a  nerve,  while  others  contain 
both  a  capillary  and  a  nerve.  The  nerves  end  in  little 
knobs,  and  it  is  by  means  of  these  nerve  ends  that  we 
feel  everything  that  touches  us. 

The  true  skin  is  so  sensitive  because  of  its  many 
nerves  that  if  the  scarf-skin  which  protects  it  is  re- 
moved, the  uncovered  place  will  smart  with  pain. 
Every  boy  knows  this  who  has  blistered  his  hands  and 
then  opened  the  blister,  to  let  the  water  out.  The 
raised  skin  that  was  above  the  water  was  scarf-skin; 
that  below  the  water  was  true  skin,  full  of  nerves, 
and  painful  if  touched,  or  even  exposed  to  the  air. 

Perspiration.— If  you  run  fast,  or  take  other  active 
exercise  on  a  warm  day,  perspiration,  or  sweat  as  it  is 
also  called,  will  appear  on  the  skin.  Perspiration  con- 
sists of  water  in  which  a  very  small  amount  of  common 
salt  and  other  matter  is  dissolved.  It  is  formed  in  the 
true  skin  in  what  are  called  sweat-glands. 

Perspiration  will  often  collect  in  drops  on  the  back 
of  your  hands,  or  run  in  little  streams  from  your 
forehead.  When  it  is  formed  slowly,  it  does  not 
collect  in  drops,  but  as  fast  as  it  is  made  it  passes 
from  the  body  in  vapor,  which  cannot  be  seen. 
Although  you  may  not  see  it,  perspiration  is  formed 
at  all  temperatures  and  at  all  times,  whether  you 


118 


PHYSIOLOGY   FOE   CHILDREN 


are    taking    exercise,   sitting    still,  or   even  lying  in 
bed. 

Sweat-glands.— On  page  119  is  a  picture  of  a  small 
piece  of  skin  which  contains  sweat-glands.  The 
lower  part  of  the  gland  is  twisted  into  a  coil,  and 
from  the  coil  a  small  tube  passes  through  both  parts 


NERVES  AND  BLOOD  TUBES  IN  TRUE  SKIN. 
(Magnified.) 

of  the  skin  and  opens  on  the  surface  of  the  scarf-skin. 
The  cells  in  the  coiled  part  of  the  sweat-gland  take 
water  and  other  materials  from  the  capillaries  sur- 
rounding them  and  make  the  perspiration,  which  then 
flows  along  the  tube  and  out  through  the  opening  on  to 
the  surface  of  the  skin. 

If  you  will  look  at  the  skin  on  the  back  of  your 
hand  with  a  strong  magnifying  glass  you  will  find  it 


THE   SKIN 


119 


dotted  all  over  with  tiny  little  holes.  These  holes  are 
the  openings  of  the  perspiration  tubes.  They  are 
called  pores,  and  there  are  more  than  two  million 
of  them  on  the  surface  of  the  body. 

Use  of  perspiration. — You 
have  seen  water  sprinkled  on  a 
floor  on  a  hot  day  and  have 
felt  the  air  in  the  room  becom- 
ing cooler  afterwards.  The  air 
became  cooler  because  some  of 
its  heat  was  taken  from  it  and 
used  to  change  the  sprinkle il 
water  into  vapor,  or  evaporate 
it.  The  cooling  of  the  body 
by  perspiration  is  caused  in 
the  same  way.  Some  of  the 
body's  heat  is  taken  from  it 
and  used  to  change  the  per- 
spiration into  vapor. 

When  your  body  is  becoming  too  warm  the  blood 
capillaries  of  the  skin  become  larger,  and  a  greater 
amount  of  blood  than  usual  flows  into  them.  The 
sweat-glands  then  work  faster,  so  that  a  great  deal 
of  perspiration  is  made,  and,  as  it  evaporates,  the  body 
becomes  cooler. 


SECTION  OF  SKIN. 

a,  Sweat-glands.    5,  Hair  shaft. 
c,  Oil-gland.  d,  Muscle. 

(Magnified.) 


120  PHYSIOLOGY   FOB   CHILDEEN 

Cold  acts  in  a  directly  opposite  way.  When  the 
body  is  cold  the  blood  tubes  of  the  skin  become 
smaller.  They  then  allow  less  blood  than  usual  to 
flow  into  them,  and  only  a  little  perspiration  is  made. 

Sometimes  when  people  are  very  warm  they  allow 
themselves  to  cool  off  too  quickly.  They  may  go  too 
soon  into  cold  air,  or  may  stand  or  sit  after  violent 
exercise  without  putting  on  extra  clothing.  This  is  a 
very  common  way  of  "  catching  cold." 

The  nails. — The  nails  on  the  upper  sides  of  the 
ends  of  the  fingers  and  toes  do  not  look  very  much 
like  scarf-skin,  yet  they  are  made  of  scarf-skin  which 
has  become  very  hard,  almost  like  horn.  The  nails 
protect  the  ends  of  the  fingers  and  toes. 

When  the  nails  are  kept  clean  and  neatly  trimmed 
they  are  not  only  useful,  but  are  also  ornamental. 
Biting  the  nails  injures  them ;  they  should  be  cut. 

The  hair. — Hair  does  not  look  at  all  like  skin,  yet 
it  is  made  of  changed  cells  of  scarf-skin.  The  lower 
end,  or  root,  of  each  hair  is  in  the  true  skin,  and  the 
hair  gets  its  nourishment  from  the  blood  in  the  capil- 
laries of  the  true  skin. 

Near  the  root  of  each  hair  are  glands  which  look 
like  little  bags.  These  are  oil-glands.  They  take 
material  from  the  blood  in  the  blood  tubes  near 


THE  SKIN 

them,  change  it  into  an  oily  substance  and  pour  it  out 
upon  the  hair  and  skin  to  keep  them  soft. 

The  hair  helps  to  protect  the  head  from  blows  or 
other  injury.  It  also  keeps  the  head  warm  and  serves 
as  an  ornament.  The  hairs  which  grow  upon  the  edge 
of  each  eyelid  are  called  eyelashes.  The  eyelashes 
catch  particles  of  floating  dust,  and  also  act  as  a 
screen  from  the  bright  sunlight.  Thus  in  two  ways 
they  protect  the  eyes. 

The  hair  and  the  scalp  should  be  washed  thoroughly 
at  least  every  two  or  three  weeks.  Begin  by  washing 
with  soap  and  water  that  is  quite  warm,  and  after- 
wards use  cold  water.  If  you  then  dry  your  hair 
thoroughly,  there  will  be  no  danger  of  taking  cold 
even  in  winter  weather. 

Care  of  the  skin.— You  have  already  learned  that 
the  water  of  perspiration  passes  off  as  vapor,  but  the 
oil  and  other  matter  cannot  evaporate.  Together 
with  the  worn-out  cells  of  the  scarf-skin,  they  form  a 
thin  layer  upon  the  surface  of  the  skin.  Part  of  the 
perspiration  is  absorbed  by  our  clothing,  and  for  this 
reason  all  clothing  worn  near  the  skin  should  be  fre- 
quently changed  and  washed. 

If  the  waste  matters  carried  out  of  the  body  by  per- 
spiration remain  upon  the  skin  and  clothing,  they  may 


122  PHYSIOLOGY  FOE  CHILDREN 

cause  disagreeable  odors,  and  interfere  with  the  health 
of  the  skin.  The  skin  and  clothing  should,  therefore, 
be  kept  clean,  for  the  sake  of  our  own  health,  and  also 
for  the  comfort  of  others. 

The  bath. — Persons  in  ordinary  health  should  take 
a  bath  at  some  time  every  day.  The  best  time  is  in 
the  morning  just  after  rising.  Those  who  are  ac- 
customed to  take  a  daily  morning  bath  find  it  so  re- 
freshing that  they  are  uncomfortable  without  it. 

Warm  water  is  more  cleansing  than  cold,  and  soap 
helps  to  remove  the  oily  matter  which  collects  upon 
the  skin.  In  order,  therefore,  to  keep  the  body  clean, 
it  is  necessary  to  use  warm  water  and  soap  in  the  bath 
at  least  once  or  twice  a  week. 

A  warm  bath  at  bedtime  is  soothing,  after  a  day  of 
hard  labor  or  excitement.  It  has  a  quieting  effect 
upon  the  nerves  and  is  a  valuable  aid  in  producing 
sleep.  But  a  warm  bath  should  not  be  taken  in  the 
morning  in  cold  weather  if  you  are  going  out  of  doors 
soon  afterwards,  for  it  expands  the  blood  tubes  of  the 
skin  ;  as  these  blood  tubes  become  larger  more  blood 
than  usual  flows  into  them,  and  with  much  blood 
cooling  rapidly  at  the  surface  of  your  body,  you  are 
likely  to  "  catch  cold." 

If  a  warm  bath  is  taken  in  the  morning,  the  body 


THE   SKIK 


123 


should  afterwards  be  sprayed  or  sponged  with  cold 
water,  to  lessen  the  risk  of  taking  cold  on  going 
out. 

Cold  water  is  much  more  bracing  than  warm.  A 
bath  is  said  to  be  cold  when  the  temperature  of  the 
water  is  about 
60  degrees  Fah- 
renheit. Few 
people  should 
use  water  that  is 
colder  than  this. 

At  first  a  cold 
bath  causes  a 
feeling  of  chilli- 
ness, because  the 
cold  contracts 
the  blood  tubes 
of  the  skin,  and 
more  blood  than 
usual  is  forced  from  the  surface  to  the  interior  of  the 
body,  so  that  the  internal  organs  receive  an  unusual 
supply.  But  the  heart  then  works  harder  and  drives 
the  blood  back  to  the  surface.  In  this  way  a  feeling 
which  is  called  a  glow  is  produced,  and  the  bath  should 
then  come  to  an  end.  If  the  body  is  now  rubbed 


A    SURF   BATH. 


124  PHYSIOLOGY   FOE   CHILDREN 

with  a  coarse  towel  until  it  is  thoroughly  dried,  a 
marked  feeling  of  comfort  will  follow. 

o 

People  who  are  accustomed  to  take  a  cold  bath 
every  morning  seldom  catch  cold. 

Swimming. — Swimming  is  a  pleasant  way  of  taking 
a  bath.  No  one  should  remain  in  the  water  more  than 
fifteen  or  twenty  minutes.  Five  minutes  are  enough 
for  some  persons.  If  the  glow  which  follows  the  first 
feeling  of  chilliness  is  followed  by  another  chilly  feel- 
ing, the  swimmer  has  been  in  the  water  too  long. 

Effect  of  alcohol  011  the  skin.  —  Alcohol,  as  we 
have  seen,  acts  upon  the  nerves  which  control  the  size 
of  the  arteries  of  the  skin  and  causes  these  arteries  to 
become  larger  than  usual.  When  the  effects  of  a  drink 
of  liquor  have  passed  away,  the  arteries  return  to  their 
former  size ;  but  the  continued  use  of  alcohol  causes 
the  arteries  to  become  permanently  enlarged.  The 
reddish  appearance  of  the  faces  of  those  who  drink  a 
good  deal  of  alcohol  is  caused  by  the  extra  amount  of 
blood  which  the  enlarged  arteries  of  the  skin  contain. 

Effect  of  alcohol  on  the  heat  of  the  body.— 
When  alcohol  enlarges  the  arteries  of  the  skin  they 
contain  more  blood  than  usual.  This  makes  the  skin 
feel  warmer  for  a  time,  because  the  greater  supply  of 
blood  at  the  surface  warms  the  nerve  endings  in  the 


THE  SKIN  125 

skin.  It  is  this  feeling  of  warmth  in  the  skin  that 
deceives  those  who  take  alcoholic  liquor  and  gives  rise 
to  the  false  notion  that  alcohol  makes  the  body  warmer 
on  a  cold  day. 

The  fact  is  that  alcohol  makes  the  body  colder  on  a 
cold  clay.  An  unusual  amount  of  blood  is  brought 
to  the  surface  of  the  body  and  is  there  exposed  to  the 
cold.  On  this  account  heat  escapes  from  the  body 
more  rapidly  than  it  would  if  no  alcohol  were  taken. 
The  feeling  of  warmth  that  comes  at  first  is  soon  fol- 
lowed by  a  temperature  which  is  lower  than  usual. 

It  is  well  known  that  Dr.  Nansen,  Lieutenant  Peary, 
and  many  other  arctic  explorers  did  not  drink  alcoholic 
liquor  when  they  were  in  polar  regions.  Yet,  if  alco- 
holic liquor  could  keep  a  man  warm,  they  would  cer- 
tainly have  used  it  in  those  regions  where  there  is  little 
to  be  seen  but  ice  and  snow. 

Years  ago,  when  the  effect  of  the  use  of  alcoholic 
liquors  was  not  so  well  understood  as  it  is  now,  they 
were  thought  to  be  good  for  almost  every  ill  and  every 
kind  of  weather.  On  a  cold  day  alcoholic  liquor  was 
taken  to  keep  one  warm,  and  on  a  hot  day  it  was  taken 
to  keep  one  cool 

The  following  letters  show  that  one  is  better  off 
without  it  both  in  cold  and  in  hot  climates, 


126  PHYSIOLOGY   FOE   CHILDEEN 

The  first  of  these  is  from  Dr.  Frederick  A.  Cook, 
who  has  had  polar  experiences  both  in  the  Arctic  and 
the  Antarctic  Oceans.  He  was  the  surgeon  on  the 
steamer  "Belgica,"  which  entered  the  Antarctic  in 
January,  1898,  to  make  explorations,  and  was  frozen 
up  in  its  ice  for  thirteen  months, 

687  Busliwick  Avenue, 
BROOKLYN,  N.  Y.,  Jan.  8,  1900. 

My  dear  Sir, 

I  have  delayed  answering  your  letter  for  some  time  because 
I  had  intended  taking  up  the  subject  with  a  view  of  writing 
an  abstract  as  to  the  uses  and  abuses  of  alcoholic  beverages  in 
polar  work ;  but  I  find  it  is  impossible  for  me  to  give  the  mat- 
ter, at  present,  even  the  few  moments  of  time  which  it  requires. 

Without  going  into  a  detailed  account  of  my  experiences, 
the  principal  expeditions  with  which  I  have  been  connected 
have  been  two;  one  where  there  was  no  alcohol  in  use  except 
upon  rare  occasions,  and  the  other  where  alcohol  in  the  form  of 
light  wines  was  in  almost  constant  use.  From  what  I  have 
thus  seen  of  the  use  of  stimulants,  I  must  hasten  to  say  that 
alcohol  in  every  form  is  decidedly  injurious  to  men  whose  en- 
durance and  strength  are  taxed  to  the  utmost. 

Alcohol,  then,  should  have  no  place  in  the  equipment  of  an 
expedition  to  the  polar  regions  except  as  a  part  of  the  medical 
supply,  and  even  for  this  purpose  it  is  seldom  useful. 
Yours  very  sincerely, 

FREDERICK  A.  COOK,  M.D. 


THE   SKIN 


127 


CANADA    LOGS. 

OTTAWA,  ONTARIO,  CANADA, 

November  21,  1899. 
Dear  Sir : 

Timber  and  logs  upon  the  Ottawa  River  and  its  tributaries 
are  cut  mainly  at  points  from  150  to  300  miles  north  of  the 
city  of  Ottawa.  The  winters  are  cold,  and  at  times  severe, 
the  thermometer  occasionally,  though  not  often,  reaching  a 
point  about  40°  F.  below  zero.  The  cutting  of  roads,  and  the 
chopping,  hewing  and  handling  of  logs  and  timber  are  heavy 
work,  and  though  the  hours  of  daily  service  for  the  men  may 
be  long,  we  find  that  wholesome  food  to  eat  and  the  universal 
tea  to  drink  are  far  better  fortifiers  against  severe  cold  and 
other  hardships  than  any  intoxicants  could  possibly  be.  The 
men,  when  the  season's  work  is  over  in  the  spring,  are,  as  a 


128  PHYSIOLOGY   FOR  CHILDREN 

rule,  in  a  much  healthier  and  stronger  condition  than  when 
they  began  their  duties  in  the  autumn.  A  proper  discipline 
therefore  demands  that  in  our  own  interest,  as  well  as  for 
the  welfare  of  our  men,  we  prohibit  the  use  of  alcoholic  liquors 
wherever  it  is  possible  for  us  to  do  so. 
Very  truly  yours, 

E.  P.  BROXSON,  Vice-President, 

The  Bronson  Company. 

The  third  letter  is  from  General  Francis  V.  Greene, 
who  commanded  the  second  Manila  expedition. 

11  Broadway, 

NEW  YORK,  November  22,  1899. 
Dear  Sir : 

Your  letter  of  November  l?th  is  received,  and  in  reply  I 
beg  to  say  that  the  second  Manila  expedition,  consisting  of 
about  3,500  troops  under  my  command,  sailed  from  San  Fran- 
cisco June  15th  and  arrived  at  Manila  July  17th,  1898.  The 
four  ships  used  as  transports  were  all  passenger  vessels,  and 
contained  the  usual  assortment  of  liquors  for  the  use  of  pas- 
sengers. The  day  before  we  sailed  I  directed  that  all  alcoholic 
liquors  be  taken  out  of  the  ships  and  placed  on  the  dock,  and 
this  was  done.  My  reason  for  this  action  was  that  I  believed 
that  the  men  would  arrive  in  a  tropical  climate  in  a  better 
condition  after  such  a  long  voyage  through  the  tropics  if  their 
systems  were  entirely  free  from  alcohol,  and  I  think  the  re- 
sult justified  this  belief.  We  landed  immediately  after  arriv- 
ing in  Manila  Bay,  and  for  the  next  three  weeks  were  sub- 
jected to  extraordinary  hardships  in  the  trenches  in  front  of 


THE   SKIN  129 

Manila.  But  the  sick  list  was  surprisingly  small,  being  less 
than  three  per  cent.,  and  considerably  less  than  it  had  been  in 
the  camp  at  San  Francisco,  before  we  sailed. 

It  is  proper  to  state  that  there  is  a  divided  opinion  as  to  the 
effect  of  alcohol  on  the  system  in  the  tropics,  but  my  experi- 
ence in  this  case,  and  what  I  had  previously  seen  in  the  West 
Indies,  confirms  me  in  the  belief  that  the  use  of  alcohol  is 
particularly  injurious  in  the  tropical  climates,  and  the  absence 
of  it  goes  a  long  way  towards  enabling  the  northern  races  to 
withstand  the  effects  of  such  climates. 

Yours  truly, 

F.  V.  GREENE. 

We  have  learned  that : 

1.  The  skin  is  a  covering  which  protects  the  body. 

2.  The  outer  or  scarf-skin  has  no  blood  tubes. 

3.  The  scarf-skin  consists  of  layers  of  cells.     The  outer  cells  are  con- 
tinually being  rubbed  off,  while  new  ones  are  being  formed  in  the  lowest 
layer. 

4.  The  true  skin  contains  both  nerves  and  blood  tubes. 

5.  The  surface  of  the  true  skin  has  many  raised  points. 

6.  Most  of  these  points  contain  a  capillary,  some  contain  a  nerve,  and 
others  a  capillary  and  a  nerve. 

7.  The  skin  contains  sweat-glands  which  make  perspiration. 

8.  One  use  of  perspiration  is  to  cool  the  body. 

9.  The  nails  and  hair  are  made  of  changed  cells  of  scarf-skin. 

10.  The  skin  should  be  kept  clean. 

11.  We  should  not  take  a  warm  bath  just  before  going  out  into  the  cold. 

12.  A  cold  bath,  followed  by  vigorous  rubbing  with  a  coarse  towel,  im 
proves  the  health. 

13.  Alcohol  enlarges  the  small  arteries  of  the  skin  and  makes  it  red. 
When  these  arteries  contain  more  blood  than  usual,  the  body  loses  too 
much  heat. 


CHAPTER  XI 

THE    BRAIN,    SPINAL    COED,    AND    NEKVES 

The  brain   as  the   organ  of  the  mind. — How 

easily  the  engine  runs  along  the  railroad  track  and 
draws  a  long  train.  But  the  engine  with  all  its 
strength  is  useless  without  an  engineer  to  control  it. 
With  his  hand  on  the  lever  he  can  stop  or  start  the 
engine  and  make  it  go  fast  or  slow  as  he  wishes. 

The  mind  is  like  the  engineer,  for  it  has  control  of 
the  body.  When  your  mind  decides  to  turn  a  leaf 
of  your  book  an  order  is  sent  out  from  your  brain 
along  certain  nerves  to  the  muscles  of  your  arm  and 
hand.  When  the  order  reaches  the  proper  muscles 
they  contract,  and  your  arm  and  hand  turn  the  leaf. 
In  the  same  manner  an  order  is  sent  out  from  your 
brain  when  you  decide  to  walk,  run,  or  move  in  any 
other  way. 

In  addition  to  the  orders  which  go-  from  the  brain 
to  muscles,  there  are  messages  which  come  to  the 
brain  from  the  ends  of  the  nerves  in  the  skin  and 
other  organs  of  the  body.  For  example,  pressure  on 
the  skin  of  your  finger  starts  a  message  which  travels 
along  a  nerve  till  it  reaches  the  brain.  It  is  only 


THE  BKAIN,    SPINAL   COED,   AND   NERVES  131 

when  this  message  reaches  the  brain  that  your  mind 
knows  your  finger  is  touching  something. 

Besides  giving  orders  and  receiving  messages,  your 
mind  can  do  other  and  higher  things.     It  can  remem- 


THE  BRAIN  AS  SEEN  FROM  ABOVE. 


ber,  it  can  imagine,  it  can  reason,  it  can  love,  it  can 
feel  happy  or  sad.  All  its  powers,  however,  act  only 
through  the  brain,  and  for  this  reason  the  brain  is 
called  the  organ  of  the  mind. 

The  appearance   of  the  brain. — The   brain  is  a 
soft  mass,  like  thick  jelly.     Its  surface  is  folded  so  as 


132  PHYSIOLOGY   FOR   CHILDREN 

to  form  ridges  with  grooves  between  them.  A  very 
deep  groove  runs  from  the  front  to  the  back  part  of 
the  brain  and  nearly  divides  it  into  two  equal  parts. 
Besides  the  large  upper  portion  of  the  brain  shown  in 
the  picture  on  page  131,  there  is  a  small  lower  por- 
tion, which  you  can  see  on  page  133. 

The  brain  is  well  supplied  with  blood  tubes.  Ar- 
teries pass  through  the  necl^  and  bring  blood  to  the 
brain  from  the  heart.  These  arteries  divide  into  a 
great  number  of  smaller  ones  which  distribute  the 
blood  to  all  parts  of  the  brain. 

As  the  brain  is  soft  it  could  be  easily  injured,  so  it 
is  placed,  for  protection,  inside  a  case  of  bone  called 
the  skull. 

The  spinal  cord  and  nerves. — The  spinal  cord, 
which  lies  within  the  spinal  column,  is  really  a  con- 
tinuation of  the  brain.  It  is  a  soft,  white  cord  about 
eighteen  inches  long.  Throughout  its  entire  length, 
glistening  silvery  threads,  called  spinal  nerves,  start 
from  it  in  pairs. 

There  are  thirty- one  pair  of  nerves  that  begin  in 
the  spinal  cord.  Each  spinal  nerve  is  made  up  of  fine 
nerve  fibres.  These  nerve  fibres  are  bound  together 
to  form  a  nerve,  just  as  telegraph  wires  are  bound 
together  to  form  a  large  cable. 


THE  BRAIN,    SPINAL   CORD,    AND   NERVES  133 


THE   BRAIN,    SPINAL   COIID,   AND   NERVES. 


134  PHYSIOLOGY  FOR   CHILDREN 

The  spinal  nerves  pass  out  into  the  body  through 
small  holes  in  the  spine.  Their  fibres  afterward 
separate  and  end  in  various  parts.  Some  end  in 
the  skin,  others  end  in  muscles,  and  others  in  dif- 
ferent internal  organs. 

Besides  those  that  begin  in  the  spinal  cord,  there 
are  twelve  pair  of  nerves  that  start  directly  from  the 
brain  and  pass  out  through  little  holes  in  the  skull. 
They  go  to  the  eyes,  ears,  mouth,  nose,  and  to  the  skin 
and  muscles  of  the  head  and  face.  A  very  important 
pair  goes  to  the  heart,  lungs,  stomach,  and  liver. 

How  the  nerves  do  their  work. — Nerve  fibres 
extend  downwards  from  the  brain  into  the  spinal 
cord.  Spinal  nerves  connecting  with  these  extend 
outwards  from  the  cord  to  the  muscles  of  the  arms, 
legs,  and  other  parts  of  the  body.  These  nerves  carry 
messages  from  the  brain  to  the  muscles,  directing 
them  to  contract.  The  nerves  can  carry  messages,  but 
cannot  start  them.  If  all  the  nerves  of  your  arm  were 
cut  you  could  not  move  the  arm,  for  no  messages 
could  go  from  the  brain  to  the  muscles  and  cause 
them  to  contract. 

Other  nerves  extending  from  the  brain  to  the  skin 
carry  messages  from  the  skin  to  the  brain  whenever 
anything  touches  the  skin.  If  all  the  nerves  extend- 


THE  BKAIN,    SPINAL   COED,    AND    NERVES  135 

ing  from  your  brain  to  one  of  your  hands  were  cut, 
you  could  not  feel  anything  with  that  hand,  for  no 
message  could  go  from  it  to  the  brain. 

Messages  carried  by  nerves  travel  very  fast.  It 
takes  only  a  very  small  part  of  a  second  for  a  mes- 
sage to  go  from  your  brain  to  your  hand,  or  from 
your  hand  to  your  brain. 


ENTERTAINING   WORK. 

Health  of  the  brain  and  nerves.— The  nervous 
system  and  the  rest  of  the  body  are  closely  united. 
The  health  of  the  one  depends  very  much  upon  the 
health  of  the  other.  When  you  are  in  good  health 
your  nerves  will  be  stronger  and  your  brain  will  be 
clearer  than  when  you  are  not  in  good  health.  Regu- 
lar meals,  regular  hours  for  work,  or  exercise,  and  for 


136  PHYSIOLOGY   FOE   CHILDREN 

rest  are  needed  as  much  for  the  brain  and  nerves  as 
for  other  parts  of  the  body. 

What  work  does  for  the  brain. — If  you  should 
keep  your  arm  tied  up  in  a  sling  for  a  long  time  it 
would  become  weak  and  would  grow  very  slowly. 
Muscular  work  makes  the  muscles  grow  and  become 
stronger,  and  brain  work  makes  the  brain  grow  and 
become  stronger.  When  you  study  well  you  are  not 
only  getting  knowledge,  but  you  are  at  the  same  time 
gaining  greater  power  of  mind.  For  this  reason  good 
work  at  school  will  make  you  able  to  use  your  brain 
well  after  you  leave  school. 

Nothing  can  be  better  for  children  than  to  have 
some  entertaining  work  in  addition  to  their  games  for 
leisure  hours.  Anything  that  one  takes  an  interest  in 
will  furnish  pleasure  and  be  the  means  of  gaining 
greater  power  of  mind. 

Sleep. — Sound  sleep  is  necessary  for  the  brain. 
During  sleep  the  brain  and  nerves  rest,  and  there  is 
time  then  to  repair  what  was  worn  out  during  the 
day,  and  also  to  lay  up  a  store  of  energy  for  the  next 
day.  You  should  take  care  to  get  plenty  of  sleep  if 
you  wish  to  grow  and  be  strong.  A  child  requires 
more  sleep  than  grown  people  because  of  his  rapid 
growth.  It  is  a  good  plan  to  have  a  regular  time  for 


THE   BRAIN,    SPINAL    COED,    AND   NERVES  137 

going  to  bed,  and  you  will  sleep  more  soundly  if  you 
spend  part  of  each  day  in  the  open  air. 

Effect  of  alcohol  on  the  brain  and  nerves. — 

The  first  effect  of  alcohol  on  the  brain  is  to  increase 
the  amount  of  blood  flowing  through  it.  This  un- 
usual amount  of  blood  in  the  brain  produces  a  state  of 
excitement,  and  while  it  lasts  the  mind  works  rapidly 
and  easily.  For  this  reason  many  are  deceived  and 
led  to  believe  that  alcohol  makes  them  able  to  think 
better  and  more  quickly. 

But  this  early  state  of  excitement  rapidly  passes 
away,  for  some  of  the  alcohol  that  is  in  the  blood 
soon  reaches  the  brain  and  numbs  the  delicate  brain 
cells.  As  a  result,  the  brain  then  has  less  power  to 
work  than  usual.  Careful  experiments  have  been 
made  which  prove  this. 

The  condition  of  intoxication  shows  very  plainly 
that  alcohol  injures  the  brain  and  nerves.  When  a 
man  is  intoxicated  it  is  impossible  for  him  to  do  any 
mental  work  well,  and  his  nerves  lose  control  over  the 
muscles,  so  that  he  can  hardly  talk,  and  can  only  stag- 
ger when  he  tries  to  walk. 

A  large  amount  of  alcohol  will  paralyze  the  brain 
and  nerves  and  produce  sleep.  In  this  condition  the 
brain  loses  all  power  to  send  out  messages  to  the  vol- 


138  PHYSIOLOGY    FOE   CHILDREN 

untary  muscles,  and  also  much  of  its  power  to  receive 
messages  from  different  parts  of  the  body. 

The  long-continued  use  of  alcohol  causes  in  many 
persons  a  terrible  disease  of  the  brain  cells  and  nerves, 
which  is  called  delirium  tremens. 

Tobacco. — When  the  leaves  of  the  tobacco  plant 
are  dried  they  are  used  for  smoking,  for  chewing,  or 
for  making  snuff. 

Tobacco  leaves  contain  a  colorless,  oily  liquid  which 
is  called  nicotine.  It  has  a  hot,  burning  taste,  and  a 
disagreeable  smell.  It  is  a  powerful  poison  and  is 
specially  harmful  to  the  nerves.  Some  nicotine  is 
taken  into  the  system  whenever  tobacco  is  smoked, 
chewed,  or  used  as  snuff. 

The  uncomfortable  effects  that  are  experienced 
when  one  is  learning  to  smoke  or  chew  are  due  to 
poisoning  by  nicotine.  Faint  ness,  dizziness,  nausea, 
extreme  weakness,  and  vomiting  are  some  of  the  most 
usual  of  these  effects.  The  skin  also  becomes  pale, 
moist,  and  cold,  and  the  pulse  exceedingly  feeble. 

After  a  time  the  tissues  of  the  body  may  become  so 
accustomed  to  this  poison  that  a  person  will  feel  scarcely 
any  inconvenience  from  it,  although  the  tissues  them- 
selves may  be  seriously  injured  by  it. 

All  agree  that  the  use  of  tobacco  is  injurious  to 


THE   BEAIN,    SPINAL   COED,    AND   NEEVES  139 

those  who  are  still  growing.  In  early  life  the  tissues 
of  the  body,  and  especially  those  of  the  nervous 
system,  are  tender  and  have  less  power  to  resist  the 
harmful  influence  of  nicotine. 

Cigarette  smoking  is  the  most  harmful  of  all  ways 
in  which  tobacco  is  used,  because  it  teaches  the  use 
of  tobacco  to  the -young.  Since  each  cigarette  is  small 
it  contains  only  a  small  amount  of  nicotine.  For 
this  reason  the  beginner  suffers  less  after  smoking  a 
cigarette  than  after  smoking  a  pipe  or  cigar.  Yet, 
one  of  the  chief  dangers  of  the  cigarette  lies  in  the 
very  fact  that  it  is  small,  for  this  is  what  makes  it 
easy  for  young  persons  to  begin  the  habit  of  smoking. 
In  a  short  time  one  cigarette  does  not  satisfy  the 
smoker,  and  he  soon  learns  to  smoke  a  large  number, 
so  that  a  dangerous  amount  of  nicotine  is  taken  into 
the  body  each  day.  Again,  the  amount  of  nicotine 
that  is  taken  into  the  body  depends  upon  the  amount 
of  surface  that  the  smoke  comes  in  contact  with. 
Cigarette  smokers,  as  a  rule,  inhale  the  smoke,  so  that 
it  comes  in  contact  with  the  mouth,  throat,  and  the 
larger  bronchial  tubes.  On  account  of  the  increased 
surface  thus  exposed  to  the  smoke,  one  who  smokes 
cigarettes  and  inhales  absorbs  a  greater  amount  of 
nicotine  than  one  who  smokes  a  pipe  or  cigar. 


140  PHYSIOLOGY   FOR   CHILDBED 

Narcotics. — Drugs  which  are  used  to  relieve  pain 
or  to  produce  sleep  are  sometimes  taken  by  persons 
who  do  not  understand  the  dangers  which  attend  their 
use.  Such  drugs,  as  opium,  laudanum,  morphine, 
chloral  and  cocaine,  are  called  narcotic  poisons  be- 
cause they  deaden  the  nerves.  They  should  be  used 
only  when  they  are  prescribed  by  a  physician,  for  an 
over-dose  of  any  of  them  will  destroy  life.  Besides 
this,  they  can  create  a  strong  desire  for  more,  just  as 
alcohol  can,  and  when  the  habit  of  using  them  is 
formed  it  is  very  difficult  to  give  them  up. 

We  liave  learned  that : 

1.  The  brain  is  the  organ  of  the  mind. 

2.  The  brain  is  soft  and  is  protected  by  the  skull. 

3.  The  surface  of  the  brain  is  folded  so  as  to  form  ridges  and  grooves. 

4.  The  spinal  cord  is  a  continuation  of  the  brain. 

5.  Nerves  extend  from  the  spinal  cord  and  the  brain  to  all  parts  of  the 
body. 

6.  Some  nerves  carry  messages  from  the  brain  to  muscles  and  cause 
them  to  contract. 

7.  Other  nerves   carry  messages  from   the  organs  of  the  body  to  the 
brain. 

8.  Sleep  is  necessary  for  the  brain  and  nerves. 

9.  Exercising  the  brain  strengthens  its  powers. 

10.  Alcohol  injures  the  cells  of  the  brain  and  nerves. 

11.  Nicotine  is  a  powerful  poison  which  injures  the  nerves. 

12.  The  use  of  tobacco  hinders  growth. 

13.  Narcotic  drugs  should  be  used  only  when  ordered  by  a  physician. 


CHAPTER   XII 

THE    FIVE    SPECIAL    SENSES 

How  the  brain  gets  information. — Imagine  a 
boy  confined  in  a  room  so  that  he  has  no  way  of 
knowing  what  takes  place  outside,  except  by  means  of 
a  telephone.  Though  lie  is  completely  shut  in,  he  can 
yet  receive  messages  and  get  information  from  the 
outside  world. 

Your  brain,  which  is  the  organ  of  the  mind,  is  shut  in 
like  the  boy ;  but  nerves,  like  telephone  wires,  extend 
from  the  brain  to  all  parts  of  the  body.  The  ends  of 
some  of  these  nerves  lie  just  under  the  scarf-skin,  the 
ends  of  some  are  in  the  tongue,  some  are  in  the  nose, 
some  in  the  eyes,  some  in  the  ears.  When  anything  from 
the  outside  world  acts  upon  these  nerves  they  carry 
messages  to  the  brain;  so  you  see  that  although  the 
brain  is  shut  within  the  skull,  yet,  through  its  nerve 
telephones,  it  receives  messages  from  the  world  outside 
the  body.  There  are  five  different  sets  of  nerve  tele- 
phones over  which  messages  thus  come  to  the  brain. 
We  call  them  the  five  special  senses, — touch,  taste, 
smell,  sight  and  hearing. 

Sometimes  a  telephone  wire  breaks,  or  is  otherwise 


142  PHYSIOLOGY   FOE  CHILDKEN 

injured,  and  then  no  messages  can  come  over  it.  It 
sometimes  happens  also  that  a  nerve  leading  from  some 
organ  of  the  body  to  the  brain  is  injured  so  that  it  will 
not  carry  any  message  to  the  brain.  It  may  be  that 
the  nerves  which  carry  messages  from  the  eyes  to  the 
brain  become  unable  to  do  their  work.  Then  we  are 
blind  and  through  our  eyes  we  can  get  no  idea  of  the 
color  and  appearance  of  the  birds,  or  flowers,  or  count- 
less things  that  others  see. 

The  sense  of  touch. — It  is  easy,  with  your  eyes 
closed,  to  tell  the  difference  between  an  apple  and  a 
peach  if  you  touch  them.  They  do  not  feel  alike. 
When  you  feel  anything  you  can  tell  whether  it  is  hot 
or  cold,  smooth  or  rough.  You  can  learn  also  some- 
thing about  its  size  and  shape. 

Nerves  extend  from  the  brain  to  the  skin.  When 
anything  touches  the  skin,  these  nerves  carry  messages 
at  once  to  the  brain  and  we  then  get  information 
about  what  we  are  touching.  It  is  by  means  of  the 
brain  and  the  nerves  of  touch  that  we  feel.  In  the 
skin  of  some  parts  of  the  body  there  are  more  nerves 
than  in  the  skin  of  other  parts.  There  are  many  nerves 
in  the  skin  on  the  tips  of  the  fingers,  while  there  are 
not  so  many  in  the  skin  on  the  back  of  the  hand.  We 
can  feel  best  with  those  parts  that  have  most  nerves. 


THE  FIVE   SPECIAL   SENSES 


143 


THOMAS    STRINGER    AND    HIS    TEACHER,    MISS    CONLEY. 

The  sense  of  touch  can  be  educated  so  as  to  become 
very  keen.  In  many  occupations  it  is  a  great  help. 
Watch  your  mother,  or  the  tailor,  examine  cloth  by 
feeling  it.  The  grocer  tests  flour  or  meal  by  rubbing 
it  gently  between  his  thumb  and  fingers,  and  the  car- 


144  PHYSIOLOGY   FOR   CHILDREN 

penter  feels  the  edge  of  his  chisel  or  plane  to  find 
out  if  it  is  sharp. 

Did  you  ever  see  blind  persons  read  with  their 
fingers  ?  Their  books  are  not  like  yours.  Their  letters 
are  not  made  with  ink,  but  are  made  by  raising  the 
paper  into  little  points.  By  passing  their  fingers  over 
these  raised  letters  the  blind  are  able  to  read  almost  as 
rapidly  as  you  can.  The  blind  use  their  fingers  so 
much  that  they  are  able,  by  feeling,  to  learn  a  great 
deal  that  we  learn  by  sight. 

For  those  who  are  without  both  sight  and  hearing, 
the  sense  of  touch  is  by  far  the  most  important  way 
in  which  messages  from  the  outside  world  come  to  the 
mind.  In  these  days  it  is  wonderful  how  much  may 
be  accomplished  by  one  who  can  neither  see  nor  hear. 

The  case  of  Thomas  Stringer  is  a  remarkable  illus- 
tration of  this.  Thomas  became  blind  and  deaf  as  a 
result  of  illness,  when  he  was  three  years  of  age. 

In  April,  1890,  when  he  was  four  years  and  nine 
months  old,  he  wras  admitted  to  the  Kindergarten  for 
the  Blind  in  Boston,  With  much  patience  he  was 
taught  at  last  to  know  letters  and  words  as  his  teacher 
spelled  them  in  his  hand  with  her  fingers,  and  also 
to  talk  by  making  letters  and  words  with  his  own 
fingers.  Later  he  learned  to  write,  and  to  read  the 


THE   FIVE   SPECIAL   SENSES  145 

raised  print  in  which  books  for  the  blind  are  printed. 
His  studies  in  the  primary  department  connected  with 
the  kindergarten  included  language,  arithmetic,  his- 
tory, geography,  physiology,  science,  and  manual  train- 
ing. When  he  was  thirteen  years  of  age  he  entered 
the  sixth  grade  of  the  Lowell  Public  Grammar  School 
of  Boston.  His  teacher  who  was  with  him  in  the 
kindergarten  went  with  him  to  the  grammar  school 
to  aid  him  in  his  studies.  The  principal  of  the 
Lowell  School,  Mr.  E.  P.  Sherburne,  writes  of  Thomas: 
He  had  no  trouble  in  maintaining  an  average  standing 
in  the  class,  or  grade,  to  which  he  belonged.  He 
entered  the  ninth  grade  in  September  (1902),  and 
graduated  in  the  following  June  with  his  classmates 
who  could  see  and  hear. 

The  sense  of  taste. — The  nerves  by  which  we 
taste  end  in  a  soft  membrane  which  covers  the  tongue 
and  some  other  parts  at  the  back  of  the  mouth.  This 
membrane  is  very  much  like  the  skin,  and  has  in  it 
little  raised  places,  in  which  these  nerves  end.  If  you 
put  a  lump  of  sugar  into  your  mouth  the  nerves  of 
taste  carry  messages  to  the  brain,  which  tell  you  that 
the  sugar  is  sweet.  It  is  by  means  of  the  brain  and 
these  nerves  that  we  taste. 

The  sense  of  taste  can  be  educated.  Many  people 
10 


146  PHYSIOLOGY   FOE   CHILDBED 

who  dislike  bananas  and  tomatoes  when  they  first 
taste  them  learn  afterwards  to  like  them  very  much. 
Children  may  dislike  the  taste  of  some  article  of  food 
that  is  useful.  By  eating  a  little  of  it  at  a  time  one 
may  learn  to  like  it ;  and  it  is  well  to  learn  to  like 
different  things,  for  variety  of  food  is  necessary  to 
keep  the  body  strong  and  healthy. 

The  sense  of  taste  gives  us  pleasure.  Children 
usually  like  sweet  things,  and  every  one  enjoys  the 
flavor  of  delicious  fruits  and  well-cooked  meals.  In- 
valids, and  others  whose  appetite  for  food  is  poor,  are 
often  induced  to  eat  freely  when  food  that  is  appetiz- 
ing is  offered  to  them,  but  will  turn  in  disgust  from 
food  that  does  not  please  their  taste. 

The  sense  of  smell. — The  sense  of  smell  is  of  value 
to  us  chiefly  in  two  v/sys.  It  is  a  source  of  pleasure. 
The  scent  of  many  flowers  is  delightful,  and  the  smell 
of  many  foods  increases  the  pleasure  of  eating.  The 
sense  of  smell  also  warns  us  against  danger.  Foul  air 
and  decayed  matter  often  tell  us  of  their  presence 
by  their  odor. 

The  fine  fibres  of  the  nerves  of  smell  are  spread  out 
in  the  lining  of  the  upper  part  of  the  nose.  When  air 
containing  an  odor  touches  the  ends  of  these  fibres 
they  carry  messages  through  the  nerves  of  smell  to  the 


THE  FIVE   SPECIAL   SENSES 


147 


brain,  and  we  know  then  what  kind  of  odor  we  are 
smelling.  It  is  by  means  of  the  brain  and  these  nerves 
that  we  smell. 

When  only  a  small  amount  of  odor  is  in  the  air  we 
get  a  faint  smell.     If  we  wish  to  smell  a  faint  odor 


THE    NERVES    OF    SMELL. 


distinctly  we  sniff,  and  so  cause  the  air  to  pass  higher 
into  the  nose  and  make  a  stronger  impression  on  the 
nerves  of  smell. 

When  we  smell  a  strong  odor,  such  as  that  of  harts- 
horn, the  power  to  smell  faint  odors  is  greatly  lessened 
for  a  time. 


148  PHYSIOLOGY   FOB  CHILDREN 

Every  one  should  be  careful  not  to  give  discomfort 
to  others  by  such  unpleasant  odors  as  are  caused  by 
eating  onions,  using  tobacco  or  liquor,  and  by  not 
keeping  the  body  and  clothing  clean. 

The  sense  of  hearing. — The  organ  of  hearing  is 
the  ear.  The  part  of  it  which  you  can  see  is  called 
the  external  ear,  and  is  made  of  cartilage  covered  with 
skin.  The  external  ear  is  of  some  use  in  collecting 
sound.  You  often  see  a  person  who  does  not  hear 
well  put  a  hand  behind  his  ear  to  aid  in  collecting 
sound.  Some  animals,  such  as  horses  and  rabbits, 
move  their  external  ears  in  order  to  catch  sounds 
better  and  to  learn  the  direction  from  which  they 
come. 

The  sounds  pass  from  the  external  ear  through  a 
little  tube,  about  an  inch  long,  into  the  head.  At  the 
inner  end  of  this  tube  there  is  a  thin  curtain  which 
separates  the  external  ear  from  the  middle  ear.  This 
curtain  is  sometimes  called  the  drum,  but  it  should  be 
called  the  drum  membrane. 

The  middle  ear  is  the  drum.  It  is  a  small  cavity 
in  one  of  the  skull  bones.  In  it  there  are  three  small 
connecting  bones.  The  first  of  these  is  fastened  to 
the  drum  membrane  at  the  outer  end  of  the  middle 
ear,  and  the  third  is  fastened  to  a  membrane  at  the 


THE  FIVE  SPECIAL   SENSES  149 

inner  end  of  the  middle  ear.  The  middle  ear  requires 
air.  This  is  supplied  it  through  a  little  tube  which 
connects  with  the  back  part  of  the  mouth. 

Just  beyond  the  middle  ear  the  skull  bone  is  hol- 
lowed out  into  a  little  chamber,  called  the  internal  ear. 
It  is  irregular  in  shape,  and  is  filled  with  a  watery 
fluid.  The  ends  of  the  nerves  of  hearing  float  in  this 
fluid. 

How  we  hear. — If  you  throw  a  stone  into  water 
little  waves  will  form  on  the  surface.  If  the  surface  is 
smooth  you  will  see  these  waves  moving  outward  in 
little  circles.  Whenever  a  bell  or  anything  capable 
of  making  a  sound  is  struck,  similar  waves  are  made 
in  the  air,  these  waves  move  outward  in  circles,  and, 
if  they  strike  against  your  ears,  cause  you  to  hear. 

You  cannot  see  these  sound  waves  because  you  can- 
not see  air.  When  they  reach  the  ear  they  travel  in- 
ward through  the  tube  of  the  external  ear,  beat  against 
the  drum  membrane  and  make  it  quiver,  or  vibrate. 
The  vibration  of  the  drum  membrane  sets  the  small 
bones  of  the  middle  ear  in  motion,  and  this  causes  the 
membrane  at  the  inner  end  of  the  middle  ear  to  vibrate. 
As  this  second  membrane  vibrates  it  sets  the  fluid  of 
the  internal  ear  in  motion.  The  waves  of  the  fluid 
then  act  upon  the  ends  of  the  nerves  of  hearing  and 


150 


PHYSIOLOGY   FOE   CHILDREN 


cause  messages  to  travel  by  these  nerves  to  the  brain. 
When  any  message  reaches  the  brain  over  these  nerves 
we  say  that  we  hear. 

Uses  of  the  sense  of  hearing. — The  sense  of  hear- 
ing warns  us  of  coming  danger.     The  Indian  puts  his 


SECTION    OF   EAR. 


ear  to  the  ground  to  hear  if  an  enemy  is  approaching. 
The  sound  of  a  bell  or  the  rumble  of  wheels  tells 
us  of  the  coming  of  a  street  car  or  wagon.  Because 
they  cannot  hear  such  warning  sounds,  deaf  people 
are  in  constant  danger  in  the  streets  of  a  crowded 
city. 

The  sense  of  hearing  gives  us  a  great  deal  of  pleas- 
ure.    There  are  very  few  people  who  do  not  enjoy 


THE  FIVE   SPECIAL   SENSES  151 

some  kind  of  music,  or  the  pleasing  voice  of  one  who 
reads  or  speaks  well. 

It  is  easy  to  shut  our  eyes  if  we  do  not  like  what  is 
before  them,  but  it  is  not  so  easy  to  close  our  ears. 
Every  one  should,  therefore,  speak  in  a  pleasing  tone  of 
voice,  and  should  be  careful  not  to  make  noises  that 
are  unnecessary  and  annoying.  Many  people  are  dis- 
turbed by  the  noises  that  others  make  thoughtlessly, 
both  in  the  house  and  in  the  street. 

Care  of  the  ears. — The  best  way  to  take  care  of 
the  ea:s  is  to  leave  them  alone.  They  are  delicate 
organs  and  can  easily  be  injured.  Never  put  any- 
thing into  the  ears.  They  should  never  be  pulled 
violently,  either  in  play  or  for  punishment.  A  blow 
on  the  ear  may  break  the  thin  drum  membrane  and 
cause  dullness  of  hearing  or  even  total  deafness. 

A  "  cold  in  the  head  "  is  a  frequent  cause  of  deaf- 
ness. Whenever  there  is  deafness  from  any  cause  a 
physician  should  be  consulted  without  delay. 

The  sense  of  hearing  can  be  wonderfully  trained. 
The  leader  of  a  band  can  often  tell  what  instrument 
among  fifty  is  half  a  tone  out  of  tune,  or  a  quarter  of 
a  beat  out  of  time.  A  railway  company  may  have 
hundreds  of  engines,  but  the  agent  at  a  station  often 
knows,  by  its  whistle,  which  engine  is  coming. 


152  PHYSIOLOGY   FOE   CHILDREN 

In  the  schoolroom  you  should  learn  to  do  two 
things, — to  attend  to  some  of  the  sounds  you  hear,  and 
to  pay  no  attention  to  others.  Practice  will  make  you 
so  perfect  that  you  will  hear  only  what  you  ought  to 
hear.  While  other  pupils  are  reciting  only  a  few  feet 
from  you,  you  will  be  able  to  study  your  history  or 
geography  as  well  as  if  you  were  the  only  one  in  the 
room. 

The  sense  of  sight.— Sight  is  a  precious  gift. 
More  pleasure  and  more  information  about  things 
around  us  come  to  us  through  the  sense  of  sight  than 
through  any  of  the  other  senses.  How  awkward  and 
difficult  it  would  be  to  travel  or  to  do  our  work  if  we 
could  not  see ! 

What  the  eye  is  like. — The  eye  is  nearly  round 
like  a  ball,  and  for  this  reason  is  sometimes  called  an 
eyeball.  It  has  an  outer  coat  which  consists  of  two 
parts.  There  is  a  clear,  glassy,  circular  part  in  f  ront, 
which  is  the  window  of  the  eye,  and  there  is  a  white 
part  which  covers  the  rest  of  the  eye.  Some  of  this 
white  part  can  be  seen,  but  most  of  it  cannot.  Both 
parts  of  the  outer  coat  are  tough  and  strong  so  as  to 
support  the  delicate  parts  inside. 

Like  all  other  parts  of  the  body  the  eye  needs 
blood  to  nourish  it.  Just  inside  the  white  part  is  a 


THE  FIVE  SPECIAL   SENSES  153 

network  of  arteries,  capillaries  and  veins.  This  net- 
work forms  the  second,  or  middle  coat  of  the  eye. 

It  would  not  be  well  for  the  eye  if  too  much  light 
were  allowed  to  come  into  it  at  one  time.  When  too 
much  sunlight  comes  in  through  our  windows  we  close 
the  curtains.  Just  inside  the  window  of  the  eye  is  a 
curtain.  It  is  called  the  iris.  The  word  iris  in  an- 
other language  means  rainbow.  It  is  the  colored  part 
of  the  eye  and  consists  of  a  circular  curtain  with  a 
small  hole,  called  the  pupil,  in  the  centre.  When  the 
light  is  too  strong  the  pupil  becomes  smaller  so  as  not 
to  admit  too  much  light.  When,  on  the  other  hand, 
the  light  is  dim,  the  pupil  becomes  larger  in  order 
to  admit  more  light. 

You  may  have  seen  boys  use  a  lens  to  collect  the 
rays  of  heat  from  the  sun  and  set  fire  to  paper  or 
wood.  Just  behind  the  iris  is  a  lens  in  the  eye  which 
looks  like  glass.  It  gathers  together  the  rays  of  light 
which  enter  the  eye,  and  causes  them  to  make  a  clear 
image  on  the  back  of  the  eye. 

The  lens  divides  the  inside  of  the  eyeball  into  two 
parts.  The  part  in  front  of  the  lens  is  smaller  than  the 
part  behind  the  lens  and  is  filled  with  a  watery  fluid. 
The  part  behind  the  lens  is  filled  with  a  thicker, 
glassy  fluid. 


PHYSIOLOGY  FOR  CHILDEEK 


The  nerves  of  sight  enter  the  eyes  at  the  back. 
The  fine  fibres  of  these  nerves  are  spread  out  in  a  thin 
layer  on  the  inner  surface  of  the  second  coat  of  each 
eye,  and  thus  form  the  third  coat. 


THE   COATS   OF  THE  EYE. 


Whenever  you  look  at  an  object  and  see  it  clearly, 
it  is  because  light  from  the  object  has  entered  the  eye 
and  made  a  picture  on  this  third  coat.  It  is  the  pic- 
ture that  causes  the  nerves  of  sight  to  carry  messages 
to  the  brain,  which  tell  us  what  we  are  looking  at. 


r. 


THE  FIVE  SPECIAL  SENSES 


155 


It  is  by  means  of  the  brain  and  the  nerves  of  sight  that 
we  see. 

The  eyelids  are  like  folding  doors.     When  they  are 
closed  they  protect  the  eyeball  from  injury. 


THE   MUSCLES   OF  THE   EYE. 


The  eyelashes,  too,  help  to  protect  the  eye  from  too 
much  light,  and  also  from  dust  and  other  small  ob- 
jects floating  in  the  air,  when  the  eyelids  are  open. 

At  the  outer,  upper  corner  of  each  eye  is  a  small 
gland  in  which  a  watery  fluid,  called  tears,  is  made. 
Generally  this  gland  makes  only  a  small  amount  of 
fluid,  but  when  you  cry  the  gland  works  rapidly  and 
tears  are  made  in  greater  quantity.  The  chief  use  of 


156  PHYSIOLOGY  FOR  CHILDREN 

tears  is  to  keep  the  eyeball  moist.  Each  time  you 
wink,  the  eyelid  moistens  the  eyeball  with  tears,  just 
as  you  may  moisten  a  piece  of  glass  with  a  damp 
sponge.  Tears  also  wash  away  particles  of  dust  that 
light  upon  the  eye. 

We  can  move  our  eyeballs.  Muscles,  as  you  see  in 
the  picture  on  page  155,  are  fastened  to  the  sides  of 
the  eyeballs.  When  one  of  these  muscles  contracts, 
it  moves  the  eye.  II  from  any  cause  the  muscles 
on  one  side  become  weak,  the  eye  may  be  turned  too 
far  toward  the  other  side.  This  condition  is  called 
squint  eye. 

Care  of  the  eyes. — The  eyes  may  easily  be  in- 
jured by  reading  fine  print  in  a  poor  light,  or  by  read- 
ing in  a  light  that  is  too  bright. 

The  direction  in  which  the  light  comes  when  you 
are  reading  is  important.  If  possible  do  not  read  or 
write  while  facing  the  light,  but  sit  so  that  the  light 
may  fall  upon  the  page  from  your  left. 

Reading  in  bed  is  a  bad  practice.  The  eyes  are 
likely  to  be  strained  because  of  the  position  of  the 
book  and  the  direction  from  which  the  light  comes  to 
the  eye.  You  should  stop  reading  the  moment  your 
eyes  smart  or  burn  or  feel  as  if  fine  sand  were  in  them. 
When  reading  you  should  stop  at  intervals  and  look 


THE   FIVE   SPECIAL   SENSES  157 

away  at  something  in  the  distance  for  a  few  minutes. 
Looking  constantly  at  near  objects  tires  the  eyes,  while 
looking  at  distant  objects  rests  them. 

Effect  of  alcohol  and  tobacco  on  the  special 
senses. — The  harmful  effect  of  alcohol  and  tobacco 
upon  the  brain  and  nerves  must  injure  the  special 
senses.  Experiments  have  shown  that  even  small 
amounts  of  alcohol  may  injure  the  sense  of  sight,  and 
also  the  sense  of  touch. 

The  use  of  tobacco  sometimes  causes  a  well-known 
disease  of  the  eye,  in  which  the  nerves  of  sight  be- 
come seriously  injured  by  inflammation.  In  this  dis- 
ease the  power  of  vision  may  be  lessened,  and  in 
severe  cases  it  may  be  entirely  lost. 


We  have  learned  that : 

1.  There  are  five  ways  in  which  messages  may  reach  the  brain. 

2.  One  of  these  ways,  the  sense  of  touch,  is  through  nerves  which  end  in 
the  skin. 

3.  We  feel  best  with  those  parts  of  the  skin  which  contain  many  nerves. 

4.  The  sense  of  touch  warns  us  of  danger,  and  gives  us  also  a  great  deal 
of  information. 

5.  A  second  way,  the  sense  of  taste,  is  through  nerves  that  end  in  the 
membrane  that  covers  the  tongue. 

6.  We  should  learn  to  like  the  taste  of  useful  articles  of  food,  if  we  do 
not  like  them. 

7.  A  third  way,  the  sense  of  smell,  is  through  the  nerves  which  end  in 
the  membrane  that  lines  the  nose. 


158  PHYSIOLOGY   FOR   CHILDREN 

8.  A  fourth  way,  the  sense  of  hearing,  is  through  nerves  that  end  in  the 
ears. 

9.  The  drum  membrane  is  stretched  across  the  inner  end  of  the  external 
ear. 

10.  In  the  middle  ear  three  small  connected  bones  connect  the  drum 
membrane  with  a  membrane  at  the  inner  end  of  the  middle  ear. 

11.  The  internal  ear  lies  behind  the  middle  ear,  and  contains  a  watery 
fluid  in  which  the  ends  of  the  nerves  of  hearing  float. 

12.  Sound  waves  of  air  beat  against  the  drum  membrane.     Each  beat  is 
repeated  ty  means  of  these  bones  on  the  inner  membrane,  and,  as  a  result, 
the  watery  fluid  behind  it  acts  upon  the  nerves  of  hearing  and  causes  us  to 
hear. 

13.  A  fifth  way,  the  sense  of  sight,  is  through  nerves  that  end  in  the 
eyes. 

14.  The  eye  has  a  strong  outer  coat  to  protect  it. 

15.  Inside  the  white  part  of  the  outer  coat  is  a  network  of  blood  tubes, 
which  forms  the  second  coat  of  the  eye. 

16.  Fibres  of  the  nerves  of  sight  are  spread  out  in  a  thin  layer  on  the 
inside  of  the  second  coat. 

17.  Rays  of  light  from  an  object  enter  the  eye  and  make  an  image  of  the 
object  on  this  layer  of  nerve  fibres,  which  cause  us  to  see  the  object. 

18.  A  little  gland  above  each  eye  supplies  it  with  a  watery  fluid  called 
tears. 

19.  Muscles  are  fastened  to  the  eyeball  and  allow  us  to  move  it  in  differ- 
ent directions. 

20.  We  should  be  careful  how  light  falls  on  the  page  we  are  reading. 


APPENDIX 

WHAT  TO  DO  BEFOEE  THE  DOCTOE 
COMES 

Accidents  happen  constantly.  Every  day  some  one 
is  cut,  or  burned,  or  swallows  poison  by  mistake,  or 
falls  and  is  badly  hurt.  As  it  is  not  always  possible 
to  secure  the  services  of  a  physician  immediately  in 
such  emergencies,  every  one  should  learn  how  to  give 
aid  to  the  injured. 

Burns  or  scalds. — The  clothing  should  be  re- 
moved with  great  care,  so  as  not  to  cause  an  increase 
of  pain,  or  to  disturb  the  injured  parts.  The  pain 
may  be  relieved  by  covering  the  burned  part  with 
cloth  that  has  been  wet  with  a  warm  solution  of 
common  baking  soda.  Apply  glycerine,  vaseline,  lard 
or  flour  to  cover  the  burned  surface  and  protect  it  from 
the  air.  Do  not  put  cold  water  on  a  burn.  Every- 
thing applied  to  a  burn  or  scald,  or  to  any  wounded 
surface,  should  be  perfectly  clean. 

Clothes  on  fire. — Very  serious  injuries  are  caused 
by  burning  clothing.  If  anybody's  clothing  catches 
fire,  wrap  tightly  about  him  a  coverlet,  co.at,  blanket, 


160  PHYSIOLOGY   FOE   CHILDEEN 

shawl,  rug,  table  cover,  or  something  of  the  kind  that 
can  be  had,  so  as  to  smother  the  flames.  If  nothing 
suitable  for  wrapping  is  at  hand,  have  him  sit  or  roll 
on  the  floor,  so  as  to  cover  the  burning  garments  with 
his  body,  and  try  to  smother  the  flames  in  that  way. 

The  person  whose  clothes  are  on  fire  should  never 
run — running  only  makes  the  fire  burn  more  quickly. 

To  avoid  swallowing  flame  when  the  clothing  is  on 
fire,  one  should  cover  the  mouth  and  nose  with  the 
arm  and  lie  down  on  the  floor. 

Fainting. — A  person  who  has  fainted  should  be 
placed  flat  on  the  side  or  back,  with  the  head  as  low 
as  the  rest  of  the  body,  or  even  a  little  lower.  If  the 
body  is  in  this  position,  blood  will  flow  to  the  head, 
and  the  faintness  will  pass  off  in  a  few  minutes. 
Always  allow  plenty  of  fresh  air. 

Smelling-salts  or  camphor  may  be  placed  under  the 
nose;  but  are  not  often  required. 

Do  not  dash  cold  water  on  a  fainting  person. 
Moisten  the  face  with  a  wet  cloth,  or  apply  to  the 
forehead  a  cloth  wet  with  cold  water.  Do  not  force 
anything  down  the  throat  of  a  person  who  is  un- 
conscious, for  he  may  in  this  way  be  choked  to 
death. 

Fits  or  convulsions. — Place  the  patient  in  a  com- 


APPENDIX 


161 


THE    POSITION    FOR    A    PERSON    WHO    HAS    FAINTED. 

fortable  position  on  the  side  or  back,  loosen  the 
clothing  so  as  to  allow  easy  breathing,  and  then  avoid 
moving  or  disturbing  him.  If  the  face  is  red,  place  the 
head  on  a  pillow ;  if  it  is  pale,  let  the  head  be  ]ow. 

Suffocation. — Suffocation  is  frequently  caused  by 
coal  gas  from  a  furnace  or  stove,  by  gas  used  for  light- 
ing houses,  by  gas  at  the  bottom  of  old  wells  or  in 
coal  mines,  and  by  the  fumes  of  burning  charcoal. 

In  a  case  of  suffocation  from  any  cause,  remove  the 
patient  at  once  to  the  open  air,  loosen  all  tight  cloth- 
ing that  hinders  breathing,  and  moisten  the  face  and 
chest  with  cold  water. 

Sunstroke. — Remove  the  patient  at  once  to  a  cool 


162 


PHYSIOLOGY   FOE   CHILDEEN 


place,  and  rub  the  body  with  ice,  or  apply  plenty  of 
cold  water. 

Frostbite. — Rub  the  frozen  part  with  snow  or  cold 
water,  then  wrap  it  in  a  wet  cloth.     The  frozen  part 
should  never  be  warmed  quickly,  but  always  slowly. 
Sting  of  bees,  wasps   and   other   insects. — Re- 
move the  sting, 
if  it  is   left  in 
the  wound,  and 
apply  ammonia 
water,    a    solu- 
tion  of  baking 
soda,  or  a  little 
wet  clay. 

Snake  bites. 
— If  the  bite  is 
on  the  hand  or 
leg,  tie  a  hand- 
ke  rchief  or 
stout  cord 
loosely  round 
the  limb  above 
the  wound  and  twist  it  tightly  with  a  stick,  to  pre- 
vent the  poison  from  being  carried  upwards  to  the 
rest  of  the  body.  Some  one  should  suck  the  wound 


TO   TREAT   SNAKE    BITE. 


APPENDIX  163 

as  quickly  as  possible,  spitting  out  what  is  thus  taken 
from  the  wound.  There  is  no  danger  in  doing  this  if 
there  are  no  sores  in  the  mouth. 

Dog  Bites. — If  the  bite  was  made  by  a  healthy 
dog,  wash  the  wound  with  clean  cold  or  hot  water, 
and  then  apply  a  pad  wet  with  water.  If  the  dog  is 
known  to  be  mad,  treat  the  bite  in  the  same  way  as  a 
snake  bite. 

Cramps.— Sudden,  sharp  pains  in  the  abdomen  are 
often  caused  by  eating  unripe  fruit,  vegetables,  or  other 
indigestible  food.  Give  castor  oil,  and  apply  cloths 
soaked  in  hot  water,  or  a  bottle  of  hot  water,  to  the 
abdomen.  If  these  measures  fail  to  give  relief  in  a 
short  time,  send  for  a  physician. 

Bleeding. — The  quickest  and  safest  way  to  stop 
bleeding  from  a  wound  of  any  kind  is  to  place  a  finger 
or  thumb  directly  upon  the  spot  that  bleeds. 

Moderate  pressure  on  the  bleeding  spot  will  stop 
the  bleeding  at  once,  whether  the  blood  comes  from  an 
artery,  from  a  vein,  or  from  capillaries. 

Keep  the  finger  applied  to  the  wound  for  ten  or  fif- 
teen minutes  and  then  remove  it  slowly. 

If  the  bleeding  begins  again,  apply  the  finger  once 
more,  and  continue  the  pressure  until  medical  aid  can 
be  secured. 


164  PHYSIOLOGY   FOE   CHILDREN 

Another  way  to  stop  the  bleeding  of  a  limb  is  by 
the  use  of  a  tourniquet.  To  make  a  tourniquet,  first  tie 
a  knot  in  the  centre  of  a  handkerchief  or  a  piece  of 
cloth.  Place  this  knot  just  above  the  bleeding  point, 
and  tie  the  ends  of  the  handkerchief  about  the  wounded 
limb.  Put  a  stick  inside  the  knot  that  ties  the  ends 
and  twist  hard  to  get  pressure  on  the  blood  tube  that 
is  bleeding. 

Nose-bleed.— Press  firmly  on  the  side  of  the  nose 
from  which  the  blood  comes,  so  as  to  close  the  bleed- 
ing nostril  completely.  At  the  same  time  incline  the 
head  slightly  forward,  to  keep  the  blood  from  running 
down  behind  into  the  throat.  If  blood  comes  from 
both  nostrils,  close  them  both  by  pressing  firmly  on 
both  sides. 

If  this  plan  fails,  the  nostril  may  be  plugged  with 
cotton,  or  with  a  plug  made  from  a  narrow  strip  torn 
from  a  clean  handkerchief  or  other  garment.  The 
strip  may  be  dipped  into  ice  water  or  alum- water,  if 
either  is  at  hand. 

Remove  the  plug  gently  after  five  or  six  hours. 

If  the  bleeding  begins  again,  put  in  another  plug 
and  send  for  a  physician. 

Be  careful  to  avoid  blowing  the  nose  for  some  time 
after  the  bleeding  stops. 


APPENDIX  165 

Foreign  bodies  in  the  nose. — If  a  foreign  body, 
such  as  a  pea  or  a  bean,  gets  into  the  nostril,  blowing 
the  nose  may  remove  it,  or  it  may  be  hooked  out  with 
a  looped  wire  or  a  hairpin. 

If  the  first  efforts  at  removal  are  not  successful, 
leave  it  alone  and  send  at  once  for  a  physician. 

Foreign  bodies  in  the  ear.— Foreign  bodies  some- 
times get  into  the  ear.  Insects  occasionally  crawl  into 
it  and  cause  great  pain.  The  delicate  drum  membrane 
may  be  injured  unless  great  care  is  used  in  removing 
such  bodies.  It 
is  therefore  much 
safer  to  have 
them  removed  by 
a  doctor. 

Foreign  bod- 
ies in  the  eye. — 

REMOVING   A    FOREIGN   BODY   FROM   THE 

A  cinder  or  a  bit  EYELID. 

of  dust  on  the  inner  surface  of  the  eyelid  or  on  the 
surface  of  the  eyeball  may  be  wiped  off  easily  with  the 
corner  of  a  clean  handkerchief,  or  be  washed  out  by 
bathing  the  eye.  If  these  simple  measures  are  not  suc- 
cessful, obtain  the  aid  of  a  physician  without  delay. 

Foreign  bodies  in  the  throat.— Small  pieces  of 
food,  bones  or  other  foreign  matter  may  become  lodged 


166  PHYSIOLOGY   FOR  CHILDREN 

in  the  throat  and  cause  choking.  If  they  are  not 
coughed  out  quickly,  they  can  often  be  removed  with 
the  first  finger. 

A  few  smart  slaps  on  the  back  between  the  shoul- 
ders, while  the  body  is  bent  forward,  will  often  give 
instant  relief. 

Such  foreign  bodies  as  coins,  pins,  bones,  and  a  great 
variety  of  similar  things,  are  sometimes  swallowed  ac- 
cidentally. 

In  such  cases  it  is  not  wise  to  give  purgatives, 
nor  is  it  wise  to  cause  vomiting.  Give  quantities  of 
mashed  potatoes  and  pancakes,  and  withhold  all  other 
food  for  a  day  or  two.  The  foreign  bodies  become 
coated  over  if  such  foods  as  these  are  given,  and  pass 
along  the  intestine  in  the  natural  way  without  doing 
harm. 

Broken  bones. — A  broken  bone  should  be  kept 
as  still  as  possible.  If  it  is  moved  about,  the  broken 
ends,  which  are  usually  sharp  and  jagged,  may  injure 
the  surrounding  soft  parts. 

A  patient  with  a  broken  bone  should  not  be  moved, 
if  he  can  be  made  comfortable  where  he  is  until  the 
doctor  comes.  The  injured  limb  should  be  supported 
on  a  pillow,  or  anything  soft,  and  kept  in  the  position 
in  which  it  is  most  comfortable. 


APPENDIX 


167 


Whenever  it  is  necessary  to  move  the  patient  before 
the  doctor  comes,  it  is  best  to  use  some  form  of  tem- 
porary support  to  keep  the  broken  bone  steady  and 
prevent  further  injury. 

In  the  fractures  of 
the  arm  or  collar 
bone,  a  sling  gives  all 
the  support  that  is 
required.  If  the  bone 
that  extends  from  the 
elbow  to  the  shoul- 
der be  fractured,  the 
sling  should  support 
the  hand  and  wrist 
only.  If  the  collar 
bone  or  the  bones 
that  extend  from  the 
elbow  to  the  wrist  be 
fractured,  the  sling 
should  be  wide  enough  to  support  the  whole  of  the 
arm  below  the  elbow. 

Splints  are  required  when  the  bones  of  the  leg  are 
broken.  A  thin  strip  of  board,  a.  walking-cane,  an 
umbrella,  or  any  straight  stick  may  be  used.  Two 
splints  should  be  employed.  One  should  be  placed  on 


A    NEATLY    BANDAGED 
ARM. 


168  PHYSIOLOGY   FOE   CHILDREN 

the  outer  side  of  the  leg  and  the  other  on  the  inner 
side.  The  splints  should  be  padded  to  prevent  pain 
from  pressure.  They  may  be  padded  with  cotton, 
pieces  of  cloth,  moss,  grass,  or  any  soft  material  at 
hand ;  and  they  should  be  held  in  place  by  bandages, 
handkerchiefs,  straps,  cords,  or  by  strips  of  cloth  of 
any  kind. 


BROKEN   LEG   IN    SPLINTS. 


Poisoning. — A  physician  should  be  sent  for  with- 
out delay  whenever  poisoning  is  suspected,  but  do  not 
wait  for  the  physician  to  come  before  trying  to  relieve 
the  patient. 

In  most  cases  of  poisoning,  tlie  first  tiling  to  do  is  to 
make  the  patient  vomit,  and  thus  expel  the  poison  from 
the  stomach.  The  exceptions  to  this  rule  are  where 
strong  acids  or  alkalis  have  been  swallowed. 

In  order  to  produce  vomiting,  give  large  quantities 
of  warm  soap  suds,  or  a  mixture  of  mustard  and  water, 
in  the  proportion  of  a  tablespoonful  of  mustard  to  a 
pint  of  water,  or  salt  and  water,  in  the  proportion  of 
two  tablespoonfuls  of  salt  to  a  glass  of  water.  If 


APPENDIX  169 

none  of  these  can  be  had  quickly,  give  large  draughts 
of  warm  water. 

One  or  two  cupfuls  of  any  one  of  these  simple 
emetics  should  be  swallowed  instantly.  Then  vomit- 
ing may  be  excited  by  putting  a  finger  down  the  throat 
or  by  tickling  the  back  part  of  the  throat  with  a 
feather.  As  soon  as  the  first  attempt  at  vomiting  is 
over,  more  water,  soap  suds,  mustard  and  water,  or  salt 
and  water,  should  be  given,  and  vomiting  should  be 
excited  again. 

Repeat  this  several  times  in  order  to  be  sure  that 
all  the  poison  is  washed  out  of  the  stomach. 

Send,  in  the  meantime,  for  the  proper  antidote  for 
the  poison  that  has  been  taken,  and  give  it  without 
delay.  The  following  is  a  list  of  common  poisons  with 
their  antidotes: 

Sulphuric  acid  or  oil  of  vitriol. — Give,  in  a  teacup 
of  water,  two  or  three  tablespoonfuls  of  any  of  the 
following :  baking  soda,  magnesia,  chalk,  whiting,  or 
plaster  from  a  wall.  Do  not  induce  vomiting. 

Oxalic  acid,  or  salts  of  lemon. — Give,  in  a  teacup  of 
water,  two  or  three  tablespoonfuls  of  chalk,  magnesia, 
whiting,  lime,  or  plaster  scraped  from  a  wall.  Do  not 
induce  vomiting. 

Carbolic  acid. — Give  twro  or  three  glasses  of  milk, 


170  PHYSIOLOGY   FOR   CHILDREN 

followed  by  two  or  three  tablespooofuls  of  sweet  oil 
or  castor  oil.  Do  not  induce  vomiting. 

Ammonia  or  hartshorn. — Give  four  tablespoonfuls 
of  vinegar  in  a  teacup  of  water,  or  give  lemon  juice  or 
orange  juice,  followed  by  two  tablespoonfuls  of  sweet 
oil.  Do  not  induce  vomiting. 

Alcohol. — Try  to  induce  vomiting.  Give  strong 
coffee,  and  apply  cold  water  to  the  head. 

Arsenic  or  Paris  green. — Try  to  induce  vomiting. 
Give  three  or  four  tablespoonfuls  of  magnesia  in  a 
teacup  of  water,  or  givo  castor  oil,  sweet  oil,  lime 
water,  raw  eggs  and  milk.  Get  dialized  iron  from  a 
drug  store.  Directions  for  its  use  accompany  the 
preparation. 

Copper  or  Hue  vitriol. — Try  to  induce  vomiting. 
Give  white  of  eggs  and  milk. 

Lead,  sugar  of  lead. — Try  to  induce  vomiting.  Give 
white  of  eggs  and  flax-seed  tea. 

Mercury,  bichloride  of  mercury  or  corrosive  subli- 
mate.— Try  to  induce  vomiting.  Give  milk,  white  of 
eggs,  and  flour  in  water. 

Opium,  or  the  following  drugs  which  are  made 
from  opium  or  contain  opium  :  morphine,  laudanum, 
paregoric,  Dover^s  powder,  Godfrey's  cordial,  soothing 
syrups. — Make  the  patient  vomit,  and  keep  him  awake 


APPENDIX  171 

by  tapping  him  on  the  forehead  with  the  finger  nails, 
or  by  striking  his  face  with  the  end  of  a  wet  towel. 
Be  very  careful  not  to  allow  him  io  become  cold.  Keep 
him  on  his  feet.  Do  not  let  him  lie  down  or  sit  down. 

PlwsphoruSj  used  in  making  matches  and  in  rat 
poison. — Try  to  induce  vomiting.  Give  two  or  three 
tablespoonfuls  of  magnesia  or  chalk  in  a  teacup  of 
water.  Avoid  giving  oil  or  fat. 

Turpentine. — Try  to  induce  vomiting.  Give  two 
tablespoonfuls  of  Epsom  salts  in  half  a  teacup  of 
water,  and  large  quantities  of  flaxseed  tea. 

Toadstools  and  poisonous  berries. — Try  to  induce 
vomiting.  Give  two  tablespoonfuls  of  Epsom  salts  in 
half  a  teacup  of  water,  and  castor  oil. 

How  to  avoid  poisoning  accidents. — These  un- 
fortunate accidents  would  scarcely  ever  occur  if  all 
bottles  and  packages  containing  poison  were  kept  by 
themselves  in  a  suitable  place.  A  bottle  of  carbolic 
acid  or  liniment,  for  example,  should  never  be  placed 
on  a  shelf  beside  a  bottle  of  medicine  that  is  intended 
for  internal  use.  It  is  dangerously  easy,  especially  at 
night,  to  mistake  one  for  the  other. 

Keep  all  poisons  locked  up  in  a  place  set  apart  espe- 
cially for  them. 

A   label,  with  the  name  of   the   contents   plainly 


172 


PHYSIOLOGY   FOR  CHILDREN 


marked  on  it,  should  be  put  on  every  bottle  or  pack- 
age, whether  it  contains  poison  or  not.  If  the  label  is 
lost,  throw  away  the  contents  of  the  package  or  bottle. 


ARTIFICIAL   INSPIRATION. 


One  mistake  may  cost  many  times  the  value  of  what 
is  thrown  away. 

What  to  do  in  a  case  of  drowning. — In  a  case  of 
drowning  the  first  thing  is  to  get  the  body  out  of  the 
water.  Unless  the  weather  is  severe,  do  not  wait  to 


APPENDIX  173 

carry  the  patient  to  a  place  of  shelter,  but  try  at  once 
to  revive  him.  There  are  two  things  that  you  want 
to  do — restore  breathing,  and  get  the  body  warm. 
Loosen  the  clothing  about  the  neck  and  chest,  and 
turn  the  body  face  down.  Then  wipe  out  the  mouth 
and  throat  with  your  finger,  covered  with  a  clean 
cloth,  or  handkerchief. 

While  the  body  is  face  downward  place  your  hands 
under  the  abdomen,  and  raise  the  body  until  the  fore- 
head just  rests  on  the  ground,  so  that  the  water  in  the 
mouth  and  throat  may  run  out. 

Then  turn  the  body  on  its  back,  and  place  a  roll  of 
clothing,  or  something  else  a  few  inches  high,  under 
the  shoulders  so  as  to  raise  the^hest.  This  straightens 
out  the  neck,  and  holds  the  chin  away  from  the  chest. 

As  the  patient  lies  on  his  back  insensible,  the  tongue 
is  apt-  to  fall  back  into  the  throat,  and  close  the  air- 
passage  which  leads  from  the  mouth  to  the  lungs. 
The  tongue,  therefore,  should  be  carefully  drawn  well 
forward,  out  of  the  mouth,  and  held  in  that  position, 
to  allow  the  free  passage  of  air  to  the  lungs.  It  can 
be  held  more  easily  if  a  handkerchief  or  cloth  is  used, 
as  in  the  picture. 

Artificial  breathing  can  then  be  produced  by  move- 
ments which  cause  the  chest  to  become  alternately 


174 


PHYSIOLOGY   FOE   CHILDREN 


larger  and  smaller,  as  in  natural  breathing.     One  of 
the  best  ways  of  doing  this  is  by  Sylvester's  method. 

Have  some  one  kneel  behind  the  head  of  the  patient, 
and  grasp  his  arms  just  below  the  elbow,  then  swing 


ARTIFICIAL   EXPIRATION. 


them  around  from  the  body  until  they  are  parallel 
with  the  head.  This  movement  causes  the  chest  to 
become  larger.  The  lungs  expand,  and  air  goes  in  to 
fill  them  as  in  natural  inspiration.  After  a  slight 


APPENDIX  175 

pause,  bring  the  arms  back  to  their  first  position  be- 
side the  body,  and  press  firmly  against  the  lower  ribs. 
This  movement  lessens  the  size  of  the  chest  and  forces 
air  out  of  the  lungs,  as  in  natural  expiration.  The 
movements  should  be  repeated  about  sixteen  times  a 
minute,  and  should  be  kept  up  either  until  natural 
breathing  is  restored,  or  until  a  physician  declares  that 
the  heart  has  ceased  to  beat. 

Since  recovery  sometimes  takes  place  after  artificial 
breathing  has  been  kept  up  for  two  or  three  hours,  do 
not  be  easily  discouraged.  Natural  breathing  com- 
mences  feebly,  and  it  should  be  aided  as  much  as  pos- 
sible by  swinging  the  arras  back  at  the  time  of  natural 
inspiration,  and  bringing  them  down  to  the  sides  at 
the  time  of  natural  expiration,  until  the  breathing  be- 
comes strong. 

Natural  breathing  may  be  stimulated  by  holding 
smelling  salts  or  hartshorn  near  the  noso,  but  strong 
hartshorn  should  not  be  held  too  close,  as  it  may  cause 
injury  to  the  inside  of  the  nose. 

Besides  working  to  restore  natural  breathing,  try  in 
every  possible  way  to  get  the  body  warm.  Have  the 
clothing  removed  as  soon  as  possible,  and  the  body 
dried  gently.  Cover  it  with  any  dry  blankets,  shawls, 
or  clothing  that  can  be  obtained.  Place  along  the 


170  PHYSIOLOGY   FOR  CHILDREN 

sides  of  the  trunk  and  limbs  any  hot  stones,  bricks, 
boards  or  sand  that  have  been  heated  by  the  sun,  or 
any  hot  water  bottles,  or  other  objects  that  can  be 
secured.  Have  the  limbs  and  trunk  rubbed  gently 
but  firmly  towards  the  chest,  so  as  to  produce  warmth, 
and  also  to  aid  the  blood  in  its  return  to  the  heart. 
As  soon  as  the  patient  can  swallow,  give  him  fre- 
quently hot  drinks,  such  as  tea,  coffee,  or  even  water. 
He  may  also  be  given,  as  a  stimulant,  half  a  teaspoon- 
ful  of  aromatic  spirits  of  ammonia  in  a  tablespoonful 
of  water,  every  half  hour,  till  the  feet  and  hands  be- 
come warm,  and  the  patient  feels  comfortable.  When 
he  feels  well  enough  to  be  removed,  he  should  be  car- 
ried carefully,  with  head  low,  and  put  into  a  warm 
bed.  Some  one  should  remain  with  him  for  a  while 
so  that  prompt  measures  may  be  taken  if  breathing 
should  again  stop. 

Causes  and  prevention  of  disease. — Disease  may 
be  caused  by  improper  food,  by  over-eating,  by  impure 
drinking  water,  by  the  use  of  alcoholic  liquors,  or  of 
tobacco,  by  unhealthf  ul  surroundings,  bad  habits,  lack 
of  exercise,  and  in  other  ways. 

Some  diseases,  such  as  measles,  scarlet  fever  and 
smallpox  are  contagious.  The  germs  which  cause 
these  diseases  are  given  off  from  the  bodies  of  those 


APPENDIX 


177 


who  are  sick  with  them,  are  carried  in  some  way 
through  the  air,  and  enter  the  bodies  of  those  who 
are  near.  The  germs  of  contagious  diseases  may  be 
carried  from  a  distance  in  letters  or  books,  clothing, 
toys,  furniture,  and  similar  objects. 

The  germ  that  causes  diphtheria  is  contained  in  the 
saliva,  and  in  the  dis- 
charges from  the  nose 
and  mouth  of  a  patient 
ill  with  this  disease, 
but  it  is  not  carried  by 
the  breath. 

Consumption  of  the 
lungs  may  be  given  to 
one  person  by  another. 
The  germ  which  causes 
consumption  is  always 
contained  in  what  a  patient,  who  is  ill  with  consump- 
tion, coughs  up.  This  is  called  the  sputum.  If  it  be- 
comes dry,  it  will  mingle  with  the  dust  in  the  air  and 
may  be  inhaled  by  others.  Both  the  patient  and  the 
family  should  do  their  best  to  prevent  this  by  dispos- 
ing of  the  sputum  in  the  right  way. 

It  may  be  received  into  a  spittoon  containing  a  lit- 
tle water,  and  afterwards  be  buried  or  emptied  into 


CONSUMPTION    GERMS.       (Magnified.) 


12 


178  PHYSIOLOGY   FOB   CHILDREN 

the  sewer.  Or  it  may  be  received  on  a  piece  of  cloth 
and  then  be  burned.  So  long  as  the  germs  are  kept 
moist,  they  are  harmless. 

Every  one  should  be  careful  not  to  use  a  cup  or 
other  drinking  vessel  that  has  been  used  by  one  who 
has  sore  throat,  sores  on  the  tongue,  in  the  mouth,  on 
the  face,  on  the  lips,  or  on  other  parts  of  the  body. 
All  those  who  have  sore  eyes,  or  any  kind  of  sores  of 
the  skin,  should  always  use  a  separate  towel. 

Great  care  should  be  taken  to  prevent,  as  far  as 
possible,  the  spread  of  contagious  disease.  In  such 
diseases  the  patient  and  his  nurse  should  be  kept 
away  from  the  rest  of  the  family,  until  all  danger  of 
contagion  is  past.  The  clothing,  rooms  and  furniture 
of  the  whole  house  should  be  thoroughly  cleaned  and 
made  harmless  according  to  the  doctor's  directions. 

Cleanliness  will  do  a  great  deal  towards  preventing 
disease.  The  germs  that  cause  disease  often  cling  to 
dust.  For  this  reason  walls,  floors,  curtains  and  cloth- 
ing should  be  kept  as  free  from  dust  as  possible. 

Flies  and  mosquitoes  often  carry  disease  germs 
and  leave  them  on  our  food,  or  force  them  into  our 
bodies.  Except  at  meal  time,  all  food  should  be  kept 
covered,  so  that  flies  cannot  get  at  it,  and  doors  and 
windows  should  be  screened  so  as  to  keep  flies  and 


APPENDIX  179 

mosquitoes  out  of  the  house.  It  has  been  shown 
by  experiment  that  malarial  and  yellow  fevers  are 
probably  due  to  mosquito  bites. 

Fresh  air  and  sunlight  are  great  purifiers.  Both 
should  be  admitted  freely  to  our  homes.  Clothing, 
bedding  and  furniture  should  from  time  to  time  be 
put  out  in  the  sunlight,  so  that  any  germs  they  may 
contain  may  be  destroyed. 

Clothing  that  is  worn  during  the  day  should  not  be 
worn  at  night,  but  should  be  hung  up,  to  air  and  dry. 


EXPERIMENTS 

(For  the  Teacher) 

A  NUMBER  of  good  specimens  for  object  lessons  in 
physiology  may  be  obtained  without  difficulty.  These 
should  be  carefully  prepared  before  they  are  brought 
into  the  class  room.  All  blood  stains  and  superfluous 
tissue,  such  as  fat  and  skin,  should  be  removed  from 
fresh  specimens  so  as  to  have  them  as  neat  as  possible. 
After  they  are  made  ready,  they  should  be  kept  in 
damp  cotton  cloth  till  they  are  used. 

In  addition  to  specimens,  a  sharp  knife,  a  pair  of 
scissors,  a  few  large  plates,  and  a  few  towels  will  be 
needed. 

BONES 

To  show  structure  of  bone. — Ask  a  butcher  to 
prepare  the  shin  bone  of  a  sheep,  or  calf,  by  sawing  it 
across  the  middle,  and  by  sawing  one  of  the  pieces 
into  halves  lengthwise. 

(1)  Show  the  central  cavity  of  the  shaft,  and  the 
ring  of  solid  bone  surrounding  it. 


EXPEKIMENTS  181 

(2)  Compare    the 
shaft  with  the  end  of 
the  bone,  and  observe 
that  there  is  no  cav- 
ity in  the  end. 

(3)  Compare     an 
old  dry  bone  with  a 
fresh  one,  and  notice 
their  different  appear- 
ance.      Small    holes 
may  be  seen  in  dried 
bones,  showing  where 
arteries     entered     to 
carry   blood   for   the 
nourishment    of    the 

BALL   AND    SOCKET   OP  HIP-JOINT. 

bones. 

Joints. — Get  a  fresh  knee-joint  from  the  fore  leg  of 
a  sheep.  Have  the  bone  cut  off  about  three  inches 
above  the  joint,  and  three  inches  below  it. 

(1)  Show    the    movement    which    this     joirit    al- 
lows. 

(2)  Cut  the  joint  open  and  show  the  joint  oil,  or 
sy  no  vial  fluid. 

(3)  Show  the  firm,  tough  ligaments  that  form  the 
side  walls  of  the  joint. 


182 


PHYSIOLOGY   FOE  CHILDREN 


Partially  dissect  out 
a  ligament,  leaving  one 
end  fastened  to  the 
bone,  and  show  its 
action. 

(4)  Show  the 
smooth  surface  of  the 
cartilage  which  covers 
the  ends  of  the  bone. 

Try  to  get  also  the 
ball  and  socket  of  the 
hip- joint  of  a  sheep. 
If  this  is  impractica- 
ble, get  the  joint  from 
a  fresh  ham,  or  the  hip-joint  of  a  chicken  or  turkey. 

(5)  Show  the  ball  of  this  kind  of  joint  and  the 
socket  into  which  it  fits.      Have  the  pupil  notice  how 
freely  the  ball  can  move   in  different  directions  in  its 
socket. 

(6)  Compare  the  freedom  of  movement  of  the  ball 
and  socket  joints  with  the  more  limited  movement  of 
the  knee-joint. 

(7)  Compare  also  the  free  movement  of  the  shoul- 
der-joints with  the  more   limited  movement  of  the 
elbow- joints. 


BALL  AND    SOCKET    OF    SHOULDER- 
JOINT. 


EXPERIMENTS  183 

MUSCLE 

Fresh,  lean  meat  of  any  kind  will  serve  well  to  illus- 
trate the  appearance  of  muscle. 

(1)  Get  a  small  piece  of  lean  corned  beef,  with  the 
fibres  running  in  the  same  direction.   After  it  has  been 
boiled,  you  will  be  able  to  separate  the  fibres  of  which 
the  muscle  is  composed,  because  boiling  softens  the 
connective  tissue  that  holds   them  together.     Use  a 
magnifying  glass  to  show  the  finest  fibres. 

(2)  Have  each  pupil  grasp  his  arm  between  the 
shoulder  and  the  elbow,  then  bend  the  arm  up  and 
down  at  the  elbow.     The  biceps  muscle  will  be  felt 
swelling  up  in  the  middle,  as  it  contracts,  and  becom- 
ing smaller,  as  it  relaxes.     Have  a  pupil  with  a  large 
biceps  bare  his  arm  and  show  the  contraction  and 
relaxation  of  the  muscle, 

(3)  Have  the  pupil  notice  the  tendons  of  the  back 
of  his  hand,  as  he  opens  and  closes  it. 

(4)  The  position  and  shape  of  some  of  the  muscles 
in  the  lower  part  of  the  leg  of  a  chicken  or  turkey  may 
be  easily  shown.    Cut  off  the  lower  part  of  the  leg  be- 
fore it  is  cooked.     Remove   the   skin   and   carefully 
separate  the  muscles. 

Show  the    thin    sheets    of    connective   tissue   that 
bind   the    muscles   together.       Show   also    how   the 


184  PHYSIOLOGY   FOR  CHILDREN 

muscles  are  attached  to  tendons.      Pull  the  tendons 
to  show  how  the  toes  are  moved. 

FOOD 

Samples  of  different  kinds  of  food  may  be  used  to 
illustrate  the  classification  of  foods. 

Proteid. — White  of  egg  is  pure  albumen,  a  well- 
known  form  of  proteid. 

(1)  Show  the  pupil  the  effect  of  heat  upon  it. 

(2)  Scrape  a  piece  of  lean  raw  beef.     The  part  that 
is  scraped  off  consists  largely  of  another  form  of  pro- 
teid.    The  shreds  that  remain  are  connective  tissue. 

(3)  Put  some  wheat   flour  in  a  little  muslin  bag, 
hold  it  under  a  stream  of  water  and  knead  it  until 
the  water  come.s  away  almost  clear.     What  remains  in 
the  bag  is  largely  gluten,  another  form  of  proteid. 

Starch  and  sugar. — Samples  of  raw  starch,  such 
as  corn  starch  or  laundry  starch,  may  be  shown.  The 
test  for  starch  is  iodine.  It  gives  starch  a  very  dark 
blue  color,  which  becomes  a  beautiful  light  blue  when 
water  is  added. 

(1)  Get  at  a  drug  store  an  ounce  of  the  tincture  of 
iodine,  a  small  spirit  lamp,  a  little  alcohol  for  the 
lamp,  and  three  or  four  test  tubes  about  six  inches 
long. 


EXPERIMENTS 


185 


(2)  Put   into   a  test 
tube  about  two  inches 
of  water,  and  about  as 
much  starch  as  will  lie 
on  the  end   of    a   pen- 
knife.    Shake  well  and 
then    boil    for    a    few 
minutes  over  the  spirit 
lamp,    until   the  starch 
becomes  clear. 

NOTE. — To  make  a  holder  for 
the    test    tube,   fold  a  piece  of 
paper  two  or  three  times,  wrap 
the  middle  of  the  paper  round        HOLDING  THE  TEST  TUBE  OVER  THE 
the  test  tube,  and  hold  the  tube  SPIRIT  LAMP* 

over  the  flame  by  the  ends  of  the  paper.  When  you  begin  to  heat  the 
test  tube,  hold  it  a  little  distance  from  the  flame,  and  move  it  around,  so 
that  the  heat  may  not  be  applied  to  just  one  place.  If  it  is,  the  glass  will 
break. 

Allow  the  contents  of  the  tube  to  cool,  pour  a  little 
into  another  test  tube,  and  add  a  drop  of  iodine  to  the 
second  tube.  The  iodine  will  give  a  very  dark  blue 
color.  Dilute  with  water,  and  the  color  will  become  a 
beautiful  light  blue. 

(3)  Take  a  small  piece  of  each  of  the   following: 
bread,  cooked  lean  meat,  cooked  fat  meat,  cooked  pota- 
toes, cooked  white  of  egg,  cooked  rice,  white  sugar, 


186  PHYSIOLOGY   FOR  CHILDREN 

soda  biscuit.  Put  a  drop  of  iodine  on  each.  Show 
the  pupil,  by  the  blue  color,  which  contain  starch  and 
which  do  not.  Test  other  kinds  of  food  for  starch. 

The  test  for  the  kind  of  sugar  contained  in  milk  is 
Fell  ling's  solution,  which  is  blue  in  color.  Get  an 
ounce  of  the  solution  and  a  few  test  tubes  from  a 
drug  store.  For  convenience  the  tubes  may  be  placed 
in  a  deep  cup  or  glass.  In  one  of  the  tubes  put  an 
inch  of  water  and  as  much  Fehling's  solution.  In 
another  put  an  inch  of  fresh  milk  and  as  much 
Fehling's  solution.  Heat  the  first  tube,  and  notice 
that  the  color  does  not  change,  even  when  the  water 
boils.  Heat  the  second,  and  you  will  find  that  the 
color  will  change  to  a  reddish  brown,  showing  the 
presence  of  sugar  in  the  milk. 

Fats. — Show  samples  of  fats.  Butter  and  lard  are 
obtained  from  animals.  Sweet  oil  and  cotton-seed  oil 
are  obtained  from  vegetables. 

Minerals. — Procure,  at  a  drug  store,  samples  of  a  few 
of  the  more  common  salts  which  are  contained  in  food, 
such  as  calcium  phosphate,  sodium  phosphate,  sodium 
bicarbonate,  and  potassium  chloride.  An  ounce  or 
more  of  each  of  these  may  be  put  into  small  bottles, 
which  should  be  labeled  and  kept  for  further  use. 
Compare  each  of  these  salts  with  ordinary  table  salt. 


EXPEEIMENTS  187 

If  possible,  secure  samples  of  so-called  mineral 
waters.  Mineral  waters  contain,  in  solution,  a  larger 
amount  of  mineral  matter  than  other  water. 


DIGESTION 


The  teeth. — Obtain  samples  of  the  different  kinds 
of  teeth  from  a  dentist,  or  get  the  tooth  of  a  sheep  or 
pig,  which  will  show  the  structure  of  the  human  tooth. 

(1)  Show  the  root,  the  crown,  and  the  enamel  to 
the  pupil. 

(2)  Break  a  tooth  with  a  hammer,  and  show  the 
pulp  cavity  and  the  channels  in  the  roots  for  nerves. 

Saliva. — To  illustrate  the  action  of  digestive  fluids, 
the  action  of  saliva  upon  starch  is  taken  because  every 
one  is  familiar  with  saliva.  Saliva  changes  starch  into 
a  kind  of  sugar,  the  test  for  which  is  Fehling's  solution. 

(1)  Put  into  a  test  tube  about  two  inches  of  water 
and  as  much  starch  as  will  lie  on  the  end  of  a  penknife. 
Shake  well,  boil  for  a  few  minutes,  and  cool. 

Put  into  another  test  tube  about  half  an  inch  of 
saliva,  and  a  very  little  of  the  boiled  starch.  Hold 
this  tube  in  warm  water  for  five  or  ten  minutes  and 
stir  contents.  Then  pour  half  of  contents  into  another 
tube  or  vessel. 

Put  a  drop  of  iodine  on  a  lump  of  white  sugar,  and 


188  PHYSIOLOGY  FOR  CHILDREN 

have  the  pupil  notice  the  reddish  brown  color.  Let  a 
drop  of  iodine  run  down  the  side  of  the  tube  or  vessel 
into  the  saliva  and  starch.  If  the  saliva  has  changed 
all  the  starch  to  sugar,  only  the  reddish  brown  color 
will  appear,  but  if  the  iodine  comes  in  contact  with 
any  unchanged  starch,  the  reddish  brown  color  will  be 
followed  by  a  dark  blue,  almost  black,  color.  Dilute 
with  water,  and  you  will  get  the  light  blue  color 
characteristic  of  the  iodine  test  for  starch. 

(2)  To  the  other  half  of  the  starch  and  saliva  add 
an   equal  quantity  of  Fehling's  solution.      Boil,  and 
the  blue  color  of  the  solution  will  change  to  a  red  or 
reddish  brown,  showing  the  presence  of  sugar. 

The  following  experiments  may  be  made  with  a  com- 
mon soda  biscuit : 

(3)  Put  a  drop  of  iodine  on  a  small  piece  of  biscuit 
and  show  the  presence  of  starch  by  the  blue  color.    Put 
the  part  of  the  biscuit  stained  dark  blue  into  water; 
stir  and  dilute,  and  you  will  get  the  light  blue  color. 

(4)  Chew  a  piece  of  the  same  biscuit  for   half  a 
minute ;  then  divide  what  has  been  chewed  into  two 
parts.     Add  a  little  water  to  one  part,  and  shake  well. 
Put  a  little  of  the  mixture  into  a  test  tube ;  add  an 
equal  quantity  of  Fehling's  solution,  and  boil.     A  red 
or  reddish    brown    color  will  be  seen,   showing  the 


EXPERIMENTS  189 

presence  of  sugar,  which  has  been  produced  by  the 
action  of  the  saliva  on  the  starch  of  the  biscuit. 

(5)  To  the  other  part  of  chewed  biscuit  add  a  drop 
of  iodine.  The  blue  color  seen  shows  the  presence 
of  starch  and  proves  that  saliva  is  able  to  change  only 
a  part  of  our  starchy  food  to  sugar. 

The  stomach. — Get  a  small  piece  of  the  wall  of  a 
pig's  stomach.  Have  the  pupil,  with  the  aid  of  a 
magnifying  glass,  find  the  opening  of  the  glands  which 
secrete  the  gastric  juice. 

The  liver  and  pancreas. — A  liver  and  a  pancreas 
from  a  sheep  or  a  pig  may  easily  be  obtained  from  a 
butcher.  These  may  be  shown  to  the  class. 

CIRCULATION 

The  pulse. — (1)  Have  the  pupil  feel  with  the  first 
finger  for  the  pulse  at  the  wrist.  It  is  best  found  at 
a  short  distance  from  the  base  of  the  thumb,  and  just 
a  little  to  the  outer  side  of  the  tendons.  Have  the 
pupil  count  the  number  of  beats  to  the  minute. 

The  heart. — Get  a  sheep's  heart  from  a  butcher. 
Ask  him  for  one  with  the  sac  still  surrounding  it,  and 
request  him  to  leave  the  large  artery  and  the  veins  for 
two  or  three  inches  above  the  heart. 

(2)  Cut  open  the  sac  which  surrounds  the  heart  and 


190 


PHYSIOLOGY   FOTC   CHILDREN 


FEELING    THE    PULSE. 


show  its  smooth, 
slippery  lining. 
This  prevents 
friction  between 
the  sides  of  the 
heart  and  the 
enclosing  sac. 

(3)  Cut  through 
the  walls  of  the 
heart  to  show 
its  c  a  v  it  ies. 
Push  a  pencil,  or 

small  twig,  down  through  the  arteries  and  veins   to 

show  that  they  open  into  the  cavities. 

THE  LUNGS 

Procure  the  fresh  lungs  and  windpipe  of  a  sheep. 
Wash  away  all  traces  of  blood,  and  remove  fat  and 
other  unnecessary  tissue. 

(l)  Have  the  pupil  examine  the  windpipe,  and 
notice  its  rings  of  cartilage.  The  lungs  may  be  in- 
flated by  pushing  a  glass  tube  well  down  into  the 
windpipe  and  blowing  into  it.  A  better  way  is  to 
insert  the  tube  of  a  bicycle  pump  well  into  the  wind- 
pipe and  then  force  air  into  the  lungs  with  the  pump. 


EXPERIMENTS  191 

(2)  Cut  away  the  parts  of  one  lung  that  surround 
the   bronchus.      Expose  the  bronchus  and  show  its 
branches.     Follow  some  of  these   branches  till  they 
become  quite  small. 

(3)  With  a  tape  line  measure  the  chest  of  a  pupil 
on  the  outside  of  the  clothing.     Have  the  class  note 
the  size  after  a  complete  expiration  and  again  after  a 
full  inspiration,  to  show  that  the  chest  increases   in 
size  during  inspiration. 

(4)  Have  each  pupil  count  the  number  of  times  he 
breathes  in  a  minute.     But  as  no  one  is  apt  to  breathe 
normally  when  he  is  thinking  about  it,  suggest  to  the 
pupil  to  count  the   number    of    respirations    to   the 
minute  of  some  one  who  does  not  know  that  he  is 
being  watched. 

(5)  Expired  air  contains  considerable  water.      To 
show  this,  breathe  on  a  mirror  and  let  the  pupil  see 
the  resultant  moisture. 

(6)  Expired    air    contains    carbon    dioxide.       To 
show     this,    have    the    pupil    blow    gently    several 
times  through  a  straw,  or  a  glass  tube,  into  a  glass 
of  lime  water.     The   lime  water  soon  becomes  milky 
in   appearance,   because   the    carbon    dioxide    unites 
with  the   lime   in  the   water,   to    form   carbonate   of 
lime. 


192  PHYSIOLOGY   FOR   CHILDREN 

Lime  water  may  be  obtained  at  a  drug  store,  or  it  may  easily  be  made. 
Take  a  quart  of  water  and  put  into  it  a  handful  of  slaked  lime.  Stir  it  well 
every  ten  or  fifteen  minutes  and  at  the  end  of  an  hour  let  it  settle.  Remove 
any  scum  lying  on  the  top  and  pour  off  the  clear  liquid. 

THE   BRAIK 

Ask  the  butcher  to  saw  open  the  skull  of  a  sheep 
carefully,  and  remove  the  brain  without  injuring  it. 
Procure  from  him  three  or  four  inches  of  the  spinal 
cord  of  the  sheep  along  with  the  brain. 

(1)  Show  the  deep  fissure  which  divides  the  brain 
into  two  equal  parts.     Show  the  wrinkled  surface  of 
the  brain,  and  pass  a  pencil  down  into  the  hollows  to 
show  their  depth. 

(2)  Point  out  some  of  the  nerves  that  start  from 
the  under  surface  of  the  brain. 

(3)  Show  that  the  brain,  as  the  spinal  cord,  extends 
downwards  into  the  spine. 


• 


KEY    TO   THE   PICTURE    ON   PAGE    11. 

windpipe  ;  b,  breastbone  ;  r,  ribs  ;  I,  lungs  ;  Ir,  liver  ;  s,  stomach  ;  i,  intestine. 


mi 

KEY   TO   THE   PICTURE   ON   PAGE    14. 

6,  blood  tubes  ;  A,  heart ;  p,  partition  between  chest  and  abdomen  ;  I,  liver  ;  $,  stomach ; 

{,  intestine. 


KEY   TO   THE   PICTURE   ON    PAGE   66. 

Stomach  in  its  natural  position, 
stomach  ;  £,  liver  ;  ^,  gall  bladder  ;  p,  pancreas  ;  i,  intestine. 


KEY   TO  THE   PICTURE    ON   PAGE    71. 

Part  of  the  stomach  cut  away,  to  show  pancreas. 

I,  liver  ;  g,  gall  bladder  ;  *,  stomach  ;  i,  intestine  ;  p,  pancreas. 


GLOSSARY 

Ab-do'men,  the  lower  part  of  the  trunk. 

al-bu'men,  a  kind  of  proteid,  as  white  of  egg. 

a-nat'o-my,  the  science  that  tells  of  the  parts  of  the 
body  and  their  arrangement. 

a-or'ta,  the  great  artery  that  starts  from  the  left  side 
of  the  heart. 

ar'ter-y,  a  blood  tube  through  which  blood  flows 
away  from  the  heart. 

bile,  a  bitter  yellowish  fluid  made  from  the  blood  by 
the  liver, 

cap'il-la'ries,  very  small  blood  tubes  that  connect 
the  arteries  and  veins. 

car'bon  di-ox'ide,  a  colorless  gas  produced  by  res- 
piration and  also  by  fermentation. 

car'ti-lage,  gristle. 

cir'cu-la'tioii,  movement    of  the  blood  through  the 

blood  tubes. 
cor'pus-cle,  a  blood  cell. 


198  PHYSIOLOGY  FOR  CHILDREN 

di-ges'tioii,  the  process  of  dissolving  and  changing 
food,  that  it  may  nourish  the  body. 

dis'til-la'tion,  the  process  of  separating  one  sub- 
stance from  another,  or  others,  by  driving  it  off 
in  vapor  and  afterwards  condensing  it. 

en-am'el,  the  hard  covering  of  the  crown  of  a  tooth. 

e-soph'a-gus,  the  tube  through  which  the  food 
passes  from  the  mouth  to  the  stomach. 

ex'pi-ra'tion,  the  act  of  breathing  out  air  from  the 
lungs. 

fer'men-ta'tion,  the  process  by  which  one  sub- 
stance is  changed  into  others  by  the  action  of 
ferments. 

gas'tric  juice,  a  thin,  acid  fluid  made  from  the  blood 
by  the  glands  of  the  stomach. 

gland,  an  organ  that  can  take  material  from  the  blood 
and  make  new  material  of  it. 

hy'gi-ene,  the  science  that  tells  how  to  preserve  and 
improve  the  health. 

in'spi-ra'tion,   the   act    of    breathing    air  into    the 

lungs. 
in-tes'tine,  the   part  of  the    digestive  tube   that  is 

below  the  stomach. 


GLOSSARY  199 

i'ris,  a  thin  colored  curtain  in  the  front  part  of  the  eye. 

lac'te-al,  a  little  tube,  in  a  villus,  that  takes  up 
digested  fat. 

lig'a-meiit,  a  band  of  connective  tissue  that  holds 
together  the  bones  of  a  joint. 

nar-cot'ic,  a  drug  which  in  small  doses  produces 
sleep,  and  in  large  doses  produces  stupor  or 
even  death. 

nic'o-tine,  a  poison  contained  in  the  leaves  of  tobacco. 
or'gan,  any  part  of  the  body  that  performs  a  special 

work. 

ox'y-geii,  one  of  the  gases  of  which  air  is  composed. 
pan'cre-as,  a  gland  that  is  behind  the  stomach. 
pan'cre-at'ic  juice,  a  digestive  fluid  made  from  the 

blood  by  the  pancreas. 
pro'te-ids,  a  class  of  substances  that  exists  in  almost 

all  animal  and  vegetable  tissues. 
pulse,  the  beating  of  the  arteries  as  the  blood  is  forced 

through  them  by  the  heart. 
sa-li'va,  the  digestive  fluid  secreted  by  the  salivary 

glands;  spittle. 
sal'i-va'ry  glands,  the  glands  that  make  saliva  from 

the  blood. 


200  PHYSIOLOGY   FOR  CHILDREN 

skel'e-ton,  the  bony  framework  of  the  body. 
spine,  the  backbone. 

sprain,  a  straining  or  twisting  of  the  ligaments  of  a 
joint. 

stom'ach,  a  muscular  sac,  or  enlargement  of  the  tube 
in  which  disgestion  is  carried  on. 

teii'don,  a  strong  cord  or  band  of  connective  tissue 
to  which  an  end  of  a  muscle  is  attached. 

tis'sue,  one  of  the  kinds  of  material  of  which  an 
organ  is  composed. 

villus,  a  hair-like  projection  from  the  inner  surface 
of  the  small  intestine. 


INDEX 


PAGE 

10 

Bleeding      ... 

PAGE 

.  163 

Air      

106 

Blood,  appearance  of 

.     83 

109 

circulation  of       . 

81,  87 

47 

clotting;  of 

.     83 

Alcohol                        .          •     • 

94 

corpuscles,  red    . 

.     83 

104 

44           white     .     . 

.     84 

effect  on  muscles 

40 

Bones  

.     17 

*'       "    employment  .     . 
44       "    stomach 

57 
74 

appearance  of      ... 
broken  . 

.     20 
166 

44       "    liver     .     .     .     . 
"       "   heart    .     .     .     . 
44       "    circulation     .     . 
"      "   arteries 

75 
90 
90 
91 

effect  of  age  on  .     .     . 
experiments  with      .     . 
how  fastened  together 
hygiene  of       ... 

.     20 

.  180 
.     21 

.     28 

44      "   blood    .     .     .     . 
4'      "   luno-s 

91 
113 

what  they  are  made  of 
Brain 

.     19 
130 

44   skin       .     .     .     . 

44       "   heat  of  body  .     . 

124 

m 

appearance  of      ... 
blood  supply        .     .     ^ 

.   131 
.  132 

44       "   brain     .     .     .     . 
44       "   nerves 

137 
137 

experiments  with 
hygiene  of 

135 

44      44    special  senses 

157 

Brandy         

96 

74 

53 

life  insurance  and 

102 

.  106 

mistaken  notions  about 

101 

.  Ill 

poisonous  action  of 

99 

Breastbone   .          ... 

.     28 

Aorta  

79 

.  109 

Arteries  .     .          ... 

78 

.  159 

Artificial  drinks 

55 

.     80 

Backbone 

25 

.     94 

Bath   .     . 

122 

in  fermentation  . 

.     94 

Beer             .          .... 

95 

.  110 

Bile 

70 

Cartilage           .          ... 

20 

202 


INDEX 


PAGE 

Cartilage,  in  spine     ....     25 

in  nose 26 

Cells    .........     12 

Cereals 53 

Cigarette-smoking     .     .     .     .139 

Circulation 81,   87 

experiments  with     .     .     .  189 

Clot  of  blood 83 

Clothing,  hygiene  of       ...     89 

on  fire    .. 159 

Collar-bone 28 

Connective  tissue  .     .     .     .  38,  63 

Convulsions 161 

Cooking 54 

Corpuscles 83 

red 83 

white 84 

Cramps 163 

Digestion 60 

experiments 187 

in  mouth 61 

in  stomach 67 

in  intestine 69 

Disease 176 

Distilled  liquor 95 

Dog  bites 163 

Drinks,  artificial 55 

Drowning 172 

Ear 148 

care  of  . 151 

foreign  bodies  in     ...  165 

Eating,  rules  for 56 

Eggs 52 

Esophagus 65 

Exercise  39 


Expiration 10? 

Eye 152 

care  of 150 

foreign  bodies  in      ...  165 

Fainting 160 

Fat 49 

Fermentation    ......     94 

Fits 161 

Food        45 

articles  of 52 

cooking  o2 54 

experiments  with     .     .     .184 

fat 49 

alcoholic  liquor  ....     97 

mineral 49 

not  easily  digested  ...54^ 

proteid 46 

starch  and  sugar      ...     47 

taken  into  blood  tubes      .     73 

Foreign  bodies  in  nose  .     .     .165 

in  car 165 

in  eye 165 

in  throat 165 

Frostbite 162 

Fruit,  as  food 53 

Gastric  juice 68 

Gland 63 

salivary 63 

gastric 68 

liver 70 

pancreas 70 

sweat .   118 

oil  gland  of  hair       .     .     .120 

tear 155 

Hair    .  .120 


INDEX 


203 


Hearing 148 

Heart 85 

how  it  works       ....     86 

beat  of 

effect  of  alcohol  on  90 

Heat  of  body 45,   97 

how  regulated     .     .     .     .119 

Hygiene  of  bath 122 

bones 28 

.brain 135,   137 

breathing Ill 

clothing 89 

cooking 55 

ear 151 

eating 56,  65 

eye 156 

hair 121 

heart 88,   90 

joints 32 

lungs 113 

muscles  ......     39 

nails 120 

nerves 135,   137 

ribs 30 

skin 121,  124 

spinal  column     ....     31 

teeth 62 

ventilation 112 

work  and  pleasure       .     .  136 

Inspiration 107 

Intestinal  juice 71 

Intestine 69 

Iris 153 

Joints 21 

Lacteals  .  73 


Lens  of  eye 153 

Ligaments 22 

Liver 70 

Lungs 108 

changes  in  blood  in  .  .119 
changes  in  air  in  .  .  .119 
experiments  with  .  .  .  190 

Malt  liquors 95 

Marrow 21 

Meat 53 

Milk 52 

Mineral  food 49 

Muscles 33 

exercise  of 39 

experiments  with     .     .     .   183 

fibres 38 

how  they  act       ....     35 

kinds 37 

shapes    .     .     ...     .     .     37 

why  they  contract  ...     37 
Nails  .........  120 

Narcotics 140 

Nerves 37,  132 

Nicotine 138 

Nose-bleed IS1 

Nose,  foreign  bodies  in  .     .     .  165 

Oil  glands 120 

Organ  '  . 9 

Oxygen  in  air  ....  81,  106 
in  blood  ....  84,  110 
u  tissues  ...  81,  84,  87 

Pancreas 70 

Pancreatic  juice 70 

Perspiration      .     .     .     .    117,  119 
Poisons    .  .  168 


204 


INDEX 


PAGE 

Proteids 46 

Pulse 88 

Sacs,  air 108,   109 

Saliva 63 

Scalds 159 

Senses,  special 141 

Sight 152 

Skeleton 18 

Skin        115 

Skull 26 

Sleep 136 

Smell 146 

Snake  bites 162 

Spinal  cord       ....       26,    132 

Spine 25 

Sprain 32 

Starch 47 

effect  of  cooking      ...     54 

Sting  of  bees .162 

Stomach 67 

Suffocation 161 

Sugar       47 

Sunstroke     .......  161 

Swallowing 65 


Sweat  glands    ......  118 

Taste       ........  145 

Tears       ........   155 

Teeth       .     .......     61 

Tendons        .......     38 


Tobacco 


138 


cigarettes  .  .139 


effect  on  muscles 
"       "    digestion 


41 
76 
92 
114 
138 
157 


'    heart    .     .     . 
"       "   throat        .     . 
"      "    nerves 
11       "    special  senses 

Touch 142 

Trunk 9 

Veins 80 

Ventilation       112 

Villi 73 

Water .  50 

Windpipe 67 

Wine 96 

Whisky 96 

Work                                           .  136 


YC  49625 


UNIVERSITY  OF  CALIFORNIA  LIBRARY 


